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YeastMine shutting down July 15

July 01, 2024

Due to ongoing cuts to our funding, SGD can no longer continue to provide the YeastMine data warehouse resource. It is with heavy hearts that we discontinue this service.

Back in 2011, SGD implemented InterMine (http://www.InterMine.org), an open source data warehouse system with a sophisticated querying interface, to create YeastMine, a multifaceted search and retrieval environment that provided access to diverse data types. YeastMine served as a powerful search interface, a discovery tool, a curation aid, and a complex database presentation format.

YeastMine has served us all quite well. We are working to move the YeastMine data into AllianceMine, hosted by the Alliance of Genome Resources, of which SGD is a founding member.

To get started with AllianceMine, go to the Templates page, and filter by category = ‘YeastMine’.

Screenshot 2024-07-01 at 9.38.37 AM

Categories: Announcements

SGD Newsletter, Summer 2024

June 20, 2024

About this newsletter:
This is the Summer 2024 issue of the SGD newsletter. The goal of this newsletter is to inform our users about new features in SGD and to foster communication within the yeast community. You can view this newsletter as well as previous newsletters, on the SGD Community Wiki.

Contents

Give a Gift / Support SGD

gift.png

Budget cuts from NIH continue to strain SGD’s finances. Despite our efforts at reducing costs, we still have significant ongoing budgetary challenges. Donations are now critical for our work to continue.

Your generous gift to SGD will help us to continue providing essential information for your research and teaching efforts. 

To contribute, please make checks payable to Stanford University, noting that “the funds should be used to support the Saccharomyces Genome Database project, under the direction of Drs. Sherlock and Cherry in the Department of Genetics, Stanford University.  Account : GHJKO, Genetics : WAZC.” 

Thank you for your support!

Kindly send by mail to:

Development Services
PO Box 20466
Stanford, CA 94309

CONTACT US: sgd-helpdesk@lists.stanford.edu

Reference genome update R64.5

SuperYeast.jpg

The S. cerevisiae strain S288C reference genome annotation has been updated to include previously unannotated features. The new genome annotation is release R64.5.1, dated 2024-05-29. Note that the underlying genome sequence itself was not altered; the chromosome sequences remain stable and unchanged.

The R64.5.1 update included:

Various sequence and annotation files are available on SGD’s Downloads site. You can find more update details on the Details of 2024 Reference Genome Annotation Update R64.5 SGD Wiki page.

Extended gene coordinates in GFF

The saccharomyces_cerevisiae.gff contains sequence features of Saccharomyces cerevisiae and related information such as Locus descriptions and GO annotations. The saccharomyces_cerevisiae.gff is fully compatible with Generic Feature Format Version 3, and is updated weekly.

In recent years, SGD has made two significant changes to the GFF content (described in more detail below):

  • In November 2020, SGD updated the file to reflect experimentally determined transcripts
  • In February 2024, SGD edited the ‘gene’ entries in the file to extend the coordinates to encompass the start and stop coordinates of the longest experimentally determined transcripts

In November 2020, SGD updated the transcripts in the GFF file to reflect the experimentally determined transcripts (Pelechano et al. 2013, Ng et al. 2020), when possible. The longest transcripts were determined for two different growth media – galactose and dextrose. When available, experimentally determined transcripts for one or both conditions were added for a gene. When this data was absent, transcripts matching the start and stop coordinates of an open reading frame (ORF) were used. 

Starting November 2020: BDH2/YAL061W with rows for longest transcripts expressed in GAL and in YPD.

Then in February 2024, SGD increased the start and stop coordinates of genes to encompass the start and stop coordinates of the longest experimentally determined transcripts, regardless of condition. This change was made in order to comply with JBrowse 2, a newer and more extensible genome browser, which requires that parent features in GFF files (genes) are larger than child features (mRNA, CDS, etc) (Diesh et al., 2023). 

After February 2024: BDH2/YAL061W with expanded start/stop coordinates for ‘gene’, still with rows for longest transcripts expressed in GAL, YPD.

GFF is a standard format used by many groups. SGD uses the GFF file to load the reference tracks in SGD’s genome browser resource.

Updates to SGD search

sgd maintenanceguy.jpeg

SGD is jam-packed with information, with new data being added every day. It’s a lot to keep up with, and with so much info, some inevitably ends up hidden from view. To make the various data types in SGD more readily accessible, we have made various improvements to the SGD search: 

  • New category for datasets. Over 3700 yeast datasets are accessible. Search by reference, keyword, assay, and lab.
  • New Strains subcategory for Reference search. Scroll down to ‘Associated Strains’ in the lefthand menu on the Search Results page.
  • Macromolecular complexes can now be searched with aliases. Further refine by reference, subunit, function, process, and location.
  • Search for alleles via their descriptions and SGDIDs. Drill down based on reference, allele type, gene, and phenotype.
  • RNA products can now be searched using RNAcentral IDs.

microPublications – latest yeast papers

MicroPub.png

​microPublication Biology is part of the emerging genre of rapidly-published research communications. microPublications publishes brief, novel findings, negative and/or reproduced results, and results which may initially lack a broader scientific narrative. Each article is peer-reviewed, assigned a DOI, and indexed through PubMed and PubMedCentral. 

Consider microPubublications when you have a result that doesn’t necessarily fit into a larger story, but will be of value to others.

Latest yeast microPublications:

All yeast microPublications can be found in SGD.

Alliance of Genome Resources – Latest Release 7.2

alliance logo.png

The Alliance of Genome Resources, a collaborative effort between SGD and other model organism databases (MODs), released version 7.2 in June 2024.

The 7.2.0 release updates the Associated Alleles and Associated Models tables on Disease pages:

  • Each table has a new column, Disease Qualifier, with a working filter. The qualifier describes whether an allele or model may be, for example, implicated in the onset of a disease or a model for the severity of a disease, respectively
  • In addition to the Disease Qualifier, the Associated Models table now has new columns for Condition Modifier and Genetic Modifier
  • The “Annotation Details” pop-up has expanded to include more information.
    • Alleles table: Association, Genetic Modifiers, Genetic Sex, Notes, and Annotation Type
    • Models table: Genetic Sex, Notes, and Annotation Type
  • The Associated Models table now has working filters for the Experimental Condition, Condition Modifier, and Genetic Modifier columns, including the ability to filter on relationship (e.g. induced by) as well as content (e.g. “copper”)
  • The Download files from the disease page Associated Alleles table and Associated Models table now include additional information as well.
    • New columns and information for the Associated Alleles table include: Allele Association, Genetic Entity Association, Disease Qualifier, Evidence Code Abbreviation, Experimental Conditions, Genetic Modifier Relation, Genetic Modifier IDs, Genetic Modifier Names, Genetic Sex, Notes, Annotation Type, Source URL, and Date.
    • New columns and information for the Associated Models table include: Model Type, Model Association, Disease Qualifier, Evidence Code Abbreviation, Experimental Conditions, Condition Modifiers, Genetic Modifier Relation, Genetic Modifier IDs, Genetic Modifier Names, Genetic Sex, Notes, Annotation Type, Source URL, and Date.

Upcoming conferences and courses

Categories: Newsletter

Reference Genome Annotation Update R64.5

June 19, 2024

The S. cerevisiae strain S288C reference genome annotation was updated. The new genome annotation is release R64.5.1, dated 2024-05-29. Note that the underlying genome sequence itself was not altered. The chromosome sequences remain stable and unchanged.

R64.5 Annotation update summary

This annotation update included (details in table below):

R64.5 Annotation update details

ChrFeatureDescription of changeReference
IIATG12/YBR217WNew uORF chrII:657824..657835, partially overlaps CDSYang Y, et al. (2023) PMID:35363116
IVYDL204W-ANew ORF chrIV:94133..94285Wacholder A, et al. (2023) PMID:37164009
VIYFR035W-ANew ORF chrVI:226260..226550Wacholder A and Carvunis AR (2023) PMID:38048358
VIIYGR016C-ANew ORF chrVII:523353..523246Wacholder A, et al. (2023) PMID:37164009, Chang S, et al. (2023) PMID:37927910
IXEFM4/YIL064WMove start 84 nucleotides downstream, new coordinates chrIX:242027..242716Hamey JJ, et al. (2024)PMID:38199565
IXYIL059CChange ORF qualifier from Dubious to Verified because stable translation product detectedWacholder A and Carvunis AR (2023) PMID:38048358
XIIIYMR106W-ANew ORF chrXIII:480924..481187Wacholder A and Carvunis AR (2023) PMID:38048358
XIVYNL040C-ANew ORF chrXIV:552558..552478Wacholder A, et al. (2023) PMID:37164009
XIVYNL155C-ANew ORF chrXIV:342135..341911Wacholder A and Carvunis AR (2023) PMID:38048358
XVATG19/YOL082WNew uORF chrXV:168632..168679Yang Y, et al. (2023) PMID:35363116
XVIATG5/YPL149W4 new uORFs: chrXVI:271236..271277, chrXVI:271252..271302, chrXVI:271299..271307, chrXVI:271302..271307Yang Y, et al. (2023) PMID:35363116
XVIATG13/YPR185WNew uORF chrXVI:907211..907351, partially overlaps CDSYang Y, et al. (2023) PMID:35363116

Categories: Data updates

Deadline extended to April 22 for the 2024 Yeast Genetics and Genomics Course

April 09, 2024

yeast_course_panorama

The application deadline for the 2024 Yeast Genetics and Genomics Course has been extended to April 22 – don’t miss your chance! Significant financial aid may be available for trainees applying, covering up to 50% of the cost of the course!

Find all the details and application form at the CSHL Meetings & Courses site.

For over 50 years, the legendary Yeast Genetics & Genomics course has been taught each summer at Cold Spring Harbor Laboratory, though the name didn’t include “Genomics” in the beginning. The list of people who have taken the course reads like a Who’s Who of yeast research, including Nobel laureates and many of today’s leading scientists.

This year’s instructors – Grant Brown, Soni Lacefield, and Greg Lang – have designed a course (July 23 – August 13) that provides a comprehensive education in all things yeast, from classical genetics through up-to-the-minute genomics. Students will perform and interpret experiments, learning about things like:

  • Transformation & Genome Engineering
  • Microscopy
  • Manipulating Yeast
  • Dissecting Tetrads
  • Isolating Mutants
  • Working with Essential Genes
  • Synthetic Genetic Arrays
  • Fluctuation Assays
  • Whole Genome Sequencing & Analysis
  • QTLMapping

Techniques have been summarized in the accompanying course manual, published by CSHL Press.

IMG_2185
There’s fierce competition between students at CSHL courses in the Plate Race, a relay in which teams carry stacks of 40 Petri dishes (used, of course).

Who should attend? Scientists who aren’t part of large, well-known yeast labs are especially encouraged to apply – for example, professors and instructors who want to incorporate yeast into their undergraduate genetics classrooms; scientists who want to transition from mathematical, computational, or engineering disciplines into bench science; and researchers from small labs or institutions where it would otherwise be difficult to learn the fundamentals of yeast genetics and genomics.

What else goes on there? Besides its scientific content, the fun and camaraderie at the course is also legendary. In between all the hard work there are late-night chats at the bar and swimming at the beach. There’s a fierce competition between students at the various CSHL courses in the Plate Race, which is a relay in which teams have to carry stacks of 40 Petri dishes (used, of course). There’s also typically a sailboat trip, a microscopy contest, and a mysterious “Dr. Evil” lab!

The Yeast Genetics & Genomics Course is loads of fun – don’t miss out!

Categories: Conferences

Tags: dna, genetics, genomics, science

New user interface for YeastMine

April 04, 2024

Here at SGD we provide high-quality curated genomic, genetic, and molecular information on the genes and gene products of the budding yeast Saccharomyces cerevisiae. Twelve years ago, in order to accommodate the increasingly complex and diverse needs of researchers for searching and comparing data, SGD implemented InterMine, an open source data warehouse system with a sophisticated querying interface, to create YeastMine.

Today’s news is that we have updated YeastMine to use the new BlueGenes user interface from InterMine. The new interface provides the same functionality you’re already familiar with, wrapped in a new design offering a more interactive experience for exploring and analyzing your data. We are making this switch because AllianceMine at the Alliance of Genome Resources, of which SGD is a founding member, is using the updated interface as well.

YeastMine is a multifaceted search and retrieval environment that provides access to diverse data types. Searches can be initiated with a list of genes, a list of Gene Ontology terms, or lists of many other data types. The results from queries can be combined for further analysis and saved or downloaded in customizable file formats. Queries themselves can be customized by modifying predefined templates or by creating a new template to access a combination of specific data types.

User documentation for the new YeastMine interface is available from InterMine.

Categories: Announcements

Tags: user-interface

Changes to Saccharomyces cerevisiae GFF3 file

March 01, 2024

The saccharomyces_cerevisiae.gff contains sequence features of Saccharomyces cerevisiae and related information such as Locus descriptions and GO annotations. It is fully compatible with Generic Feature Format Version 3. It is updated weekly.

After November 2020, SGD updated the transcripts in the GFF file to reflect the experimentally determined transcripts (Pelechano et al. 2013, Ng et al. 2020), when possible. The longest transcripts were determined for two different growth media – galactose and dextrose. When available, experimentally determined transcripts for one or both conditions were added for a gene. When this data was absent, transcripts matching the start and stop coordinates of an open reading frame (ORF) were used. 

Old version: BDH2/YAL061W with longest transcripts expressed in GAL and in YPD.

Beginning in February 2024, SGD increased the start and stop coordinates of genes to encompass the start and stop coordinates of the longest experimentally determined transcripts, regardless of condition.  This change was made in order to comply with JBrowse 2, a newer and more extensible genome browser, which requires that parent features in GFF files (genes) are larger than child features (mRNA, CDS, etc) (Diesh et al., 2023). 

After February 2024: BDH2/YAL061W with increased start/stop coordinates.

This is a standard format used by many groups. SGD uses the GFF file to load the reference tracks in SGD’s genome browser resource.

Categories: Announcements, Data updates

Tags: biology, blog, genetics, news, Saccharomyces cerevisiae

Apply Now for the 2024 Yeast Genetics and Genomics Course

February 13, 2024

yeast_course_panorama

For over 50 years, the legendary Yeast Genetics & Genomics course has been taught each summer at Cold Spring Harbor Laboratory, though the name didn’t include “Genomics” in the beginning. The list of people who have taken the course reads like a Who’s Who of yeast research, including Nobel laureates and many of today’s leading scientists.

The application deadline is March 31st, so don’t miss your chance!

Find all the details and application form at the CSHL Meetings & Courses site. This year’s instructors – Grant Brown, Soni Lacefield, and Greg Lang – have designed a course (July 23 – August 13) that provides a comprehensive education in all things yeast, from classical genetics through up-to-the-minute genomics. Students will perform and interpret experiments, learning about things like:

  • Transformation & Genome Engineering
  • Microscopy
  • Manipulating Yeast
  • Dissecting Tetrads
  • Isolating Mutants
  • Working with Essential Genes
  • Synthetic Genetic Arrays
  • Fluctuation Assays
  • Whole Genome Sequencing & Analysis
  • QTLMapping

Techniques have been summarized in the accompanying course manual, published by CSHL Press.

IMG_2185
There’s fierce competition between students at CSHL courses in the Plate Race, a relay in which teams carry stacks of 40 Petri dishes (used, of course).

Who should attend? Scientists who aren’t part of large, well-known yeast labs are especially encouraged to apply – for example, professors and instructors who want to incorporate yeast into their undergraduate genetics classrooms; scientists who want to transition from mathematical, computational, or engineering disciplines into bench science; and researchers from small labs or institutions where it would otherwise be difficult to learn the fundamentals of yeast genetics and genomics.

What else goes on there? Besides its scientific content, the fun and camaraderie at the course is also legendary. In between all the hard work there are late-night chats at the bar and swimming at the beach. There’s a fierce competition between students at the various CSHL courses in the Plate Race, which is a relay in which teams have to carry stacks of 40 Petri dishes (used, of course). There’s also typically a sailboat trip, a microscopy contest, and a mysterious “Dr. Evil” lab!

The Yeast Genetics & Genomics Course is loads of fun – don’t miss out!

Categories: Conferences

SGD Newsletter, December 2023

December 13, 2023

About this newsletter:
This is the December 2023 issue of the SGD newsletter. The goal of this newsletter is to inform our users about new features in SGD and to foster communication within the yeast community. You can view this newsletter, as well as previous newsletters, on the SGD Community Wiki.

Contents

Reference Genome Annotation Update R64.4

The S. cerevisiae strain S288C reference genome annotation was updated. The new genome annotation is release R64.4.1, dated 2023-08-23. Note that the underlying genome sequence itself was not altered in any way.

This annotation update included:

new uORFs for 3 ORFs:

8 new ncRNAs:

3 ORFs demoted from ‘Uncharacterized’ to ‘Dubious’ based on request from NCBI because they overlap tRNAs:

Various sequence and annotation files are available on SGD’s Downloads site. You can find more update details on the Details of 2023 Reference Genome Annotation Update R64.4 SGD Wiki page.

Full-text search tool Textpresso updated

SGD’s instance of Textpresso has recently been updated! Each week, SGD biocurators triage new publications from PubMed to load the newest yeast papers into the database. Once they are in SGD, those papers get indexed and loaded into Textpresso – a tool for full-text mining and searching. 

This is the new part: Content updates in SGD’s Textpresso are now happening on a weekly basis, meaning you can search full text of the very latest yeast papers!

You already love Textpresso for searching full text and its other bells and whistles:

  • Search results shown in the context of the full text – hits to query terms highlighted in situ
  • Custom corpus creation – you can decide which papers to search
  • Search using Boolean operators
  • Search scope options for document or sentence
  • Search location options can constrain to specific sections of papers

Textpresso can be accessed via the “Full-text Search” link under “Literature” in the purple toolbar that runs across the top of most SGD webpages. Now you can search full text of the very latest yeast papers each week!

Biochemical Pathways now in SGD Search

YeastPathways, which is the database of metabolic pathways and enzymes in the budding yeast Saccharomyces cerevisiae, is manually curated and maintained by the curation team at SGD.

This resource is jam-packed with information, but somewhat hidden from view. To make the pathways more readily accessible, some time ago we added a new section with pathways links on the relevant gene pages. Now the pathways are available in SGD Search!

The category “Biochemical Pathways” is now available, with facets (i.e., subcategories) for References and Loci. For even easier access, we also added the Pathway names and IDs to the autocomplete in the Search box, to enable quick browsing. Enjoy!

microPublications – latest yeast papers

​microPublication Biology is part of the emerging genre of rapidly-published research communications. We are seeing a strong set of microPublications come through the database and are glad for this venue to publish brief, novel findings, negative and/or reproduced results, and results which may initially lack a broader scientific narrative. Each article is peer-reviewed, assigned a DOI, and indexed through PubMed and PubMedCentral.

Consider microPubublications when you have a result that doesn’t necessarily fit into a larger story, but will be of value to others.

Latest yeast microPublications:

All yeast microPublications can be found in SGD.

Updates to SGD’s YeastMine data warehouse

Allele SGDIDs added to YeastMine

YeastMine is SGD’s data warehouse, powered by InterMine. We have so many templates (i.e., pre-defined queries) that provide access to so many different kinds of data.

A big area of focus for SGD and the yeast community is alleles. Alleles are different versions of genes that vary in DNA and sometimes protein sequence. Did you know that you can easily and quickly get all curated yeast allele data directly from YeastMine?

The Genes -> Alleles template returns data for one gene or a list of genes or the entire genome! Data include standard and systematic names for genes, gene name descriptions, allele names and descriptions, allele types, aliases, and references. SGDIDs for genes are included, and now SGDIDs for the alleles have been added. Previously, this query returned all of these data without the SGDIDs for the alleles. Based on user feedback, we have now made these allele SGDIDs available, so that they can be used to identify and distinguish different alleles.

Downloads files added to YeastMine

Back in the day, SGD maintained an FTP site to distribute data in various files. More recently, you have found these files in the SGD Downloads site. We have now moved these files to YeastMine:

From the YeastMine homepage, click Templates at top left. In the Filter, select ‘Downloads’ to constrain the list of templates.

The following query templates are listed under Downloads:

For help using YeastMine, please see the SGD Help Pages and our YeastMine playlist on the SGD YouTube Channel.

Chemical structures now on Chemical pages in SGD

SGD curators use the Chemical Entities of Biological Interest (ChEBI) Ontology, maintained by EMBL-EBI, to describe chemicals used in experiments curated from yeast publications and displayed on SGD webpages.

You may have noticed that we have recently added chemical structures provided by ChEBI to the Chemical pages in SGD! Click the structure to zoom in, click again to zoom back out.

It’s a small detail, but we love this feature, and hope that you do too! Thanks, ChEBI!

Alliance of Genome Resources – Release 6.0

The Alliance of Genome Resources, a collaborative effort between SGD and other model organism databases (MOD), released version 6.0 in September 2023.

Version 6.0 adds new features to gene pages:

  • New Paralogy section. Similar to Orthology, the Paralogy data are sourced from the DRSC’s DIOPT tool, which lets you view predictions from several tools at one time. Each table is ranked based on similarity, identity, alignment length, and a count of algorithms (methods) used to predict a paralogous match. See human HSPA1A gene page for an example.
  • New Sequence Detail section. For different transcripts of the gene, you can choose to view the sequence for the gene, or its CDS, cDNA, protein, gene with collapsed introns, or genomic sequence with or without 500 bp up and downstream.
  • Disease Qualifier. The qualifier describes whether a gene may be, for example, a marker_for the onset of a disease, or implicated_in the severity of a disease.
  • Disease “Annotation details”. The pop-up for individual table rows has expanded to include Association, Additional Implicated Genes, Genetic Modifiers, Strain Background, Genetic Sex, Notes, and Annotation Type.
  • The Download file from the gene page disease table now includes fields for Additional Implicated Gene ID, Additional Implicated Gene Symbol, Gene Association, Genetic Entity Association, Disease Qualifier, Evidence Code Abbreviation, Experimental Conditions, Genetic Modifier Relation, Genetic Modifier IDs, Genetic Modifier Names, Strain Background ID, Strain Background Name, Genetic Sex, Notes, Annotation Type, and Source URL.
  • The Source column entries now link back to their respective resource webpages.

SGD’s Social Media Footprint is Expanding

Discourse, Mastodon, BlueSky – oh my! Social media is in a chaotic period, with once tight-knit communities having been dismantled and thrown into the ether. SGD feels your pain; we have been searching for our audience, waiting for the stardust to settle, coagulate, coalesce…. In the interim, in an effort to reach you, we have set up SGD outposts on various platforms:

Discourse: The Alliance of Genome Resources Community Forum brings together communities of the major model organisms – yeast, worm, fly, zebrafish, frog, rat, and mouse – in one place. Users can create accounts to post announcements and questions, and chat with other researchers in a science-focused arena. Contact SGD for an invited account, which has additional permissions.

Mastodon: We’re just getting started with Mastodon; follow SGD at @yeastgenome@genomic.social

BlueSky: We’ve also just begun with BlueSky; follow SGD at @yeastgenome.bsky.social

We will be cross-posting to the various accounts – come find SGD on these platforms and we can navigate this latest social media adventure together!

Upcoming Conferences and Courses

Happy Holidays from SGD!

We want to take this opportunity to wish you and your family, friends and lab mates the best during the upcoming holidays. Stanford University will be closed for two weeks starting December 21, reopening on January 4th, 2024. Although SGD staff members will be taking time off, the website will be up and running throughout the winter break, and we will resume responding to user requests and questions in the new year.

Note: If you no longer wish to receive this newsletter, please contact the SGD Help Desk at sgd-helpdesk@lists.stanford.edu.

Categories: Newsletter

Tags: Newsletter

Search full-text with Textpresso: new papers added weekly

December 06, 2023

SGD’s instance of Textpresso has recently been updated! Each week, SGD biocurators triage new publications from PubMed to load the newest yeast papers into the database. Once they are in SGD, those papers get indexed and loaded into Textpresso – a tool for full-text mining and searching. This is the new part: Content updates in SGD’s Textpresso are now happening on a weekly basis, meaning you can search full text of the very latest yeast papers!

You already love Textpresso for searching full text and its other bells and whistles:

  • Search results shown in the context of the full text – hits to query terms highlighted in situ
  • Custom corpus creation – you can decide which papers to search
  • Search using Boolean operators
  • Search scope options for document or sentence
  • Search location options can constrain to specific sections of papers

Textpresso can be accessed via the “Full-text Search” link under “Literature” in the purple toolbar that runs across the top of most SGD webpages. Now you can search full text of the very latest yeast papers each week!

Categories: Announcements

Fpt1p is a negative regulator of RNA Polymerase III embedded in the tDNA chromatin-proteome

November 27, 2023

Gene transcription is facilitated by RNA polymerase enzyme complexes that collaborate with transcription factors, repressors, chromatin remodelers, and other cellular factors. RNA Polymerase III (RNAPIII) mainly transcribes short DNA fragments called tDNAs, that code for transfer-RNAs (tRNAs). In repressive conditions, tDNA transcription is repressed by the well-characterized protein Maf1. A new study by Van Breugel et al., recently published in Molecular Cell, identified Fpt1p (YKR011C) as an additional regulator of RNAPIII in S. cerevisiae.  

By using Epi-Decoder, a technique based on synthetic genetic array (SGA), chromatin immunoprecipitation and DNA-barcode sequencing, the local chromatin-proteome of a single tDNA was decoded in active and repressive conditions. The authors found major reprogramming of the core RNAPIII transcription machinery and other known chromatin-binding proteins. Surprisingly, they found the protein Ykr011c to be enriched in the tDNA chromatin-proteome, especially under repressive conditions, prompting the authors to rename the gene FPT1 (Factor in the Proteome of tDNAs number 1).

Following up on the Epi-Decoder finding, genome-wide sequencing methods such as ChIP-seq and ChIP-exo revealed that Fpt1p uniquely binds RNAPIII-regulated genes. Using the anchor away system to conditionally deplete core RNAPIII transcription factors from the nucleus, Fpt1 binding to tRNA genes was found to require both TFIIIB and TFIIIC but not RNAPIII or ongoing transcription. tRNA genes have been described to differentially respond to repressive signals but gene-specific regulatory mechanisms have largely remained elusive. Looking at Fpt1p, Van Breugel et al. found a correlation between tDNA responsiveness to repressive signals and Fpt1p occupancy, suggesting a negative regulatory role for Fpt1p. Substantiating these results, FPT1 knockout strains showed increased occupancy of RNAPIII and TFIIIB at tRNA genes, while TFIIIC occupancy decreased. These outcomes point towards a role for Fpt1p in promoting eviction of RNAPIII upon repressive signals. 

In summary, taking advantage of multiple yeast genetic approaches, Van Breugel et al. found that the previously uncharacterized protein Fpt1 is a bona fide RNAPIII regulator in S. cerevisiae. Their research emphasizes the importance of not overlooking uncharacterized proteins, as they may possess alternative regulatory roles that could change our views on fundamental cellular processes.

Text and image provided by Marlize van Breugel, MSc.

Categories: News and Views

Tags: RNA polymerase III, Saccharomyces cerevisiae

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