Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA380015 | ENA |
REPOSITORIES: ENA
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Project description:The essential process of pre-mRNA splicing must occur with high fidelity and efficiency for proper gene expression. The spliceosome employs DExD/H box helicases to promote on-pathway interactions while simultaneously minimizing errors. Prp8 and Snu114, an EF2-like GTPase, regulate the activity of the Brr2 helicase, promoting RNA unwinding by Brr2 at appro-priate points in the splicing cycle and repressing it at others. Mutations linked to Retinitis Pig-mentosa (RP), a disease that causes blindness in humans, map to the Brr2 regulatory region of Prp8. Previous In vitro studies of homologous mutations in Saccharomyces cerevisiae show that Prp8-RP mutants cause defects in spliceosome activation. Here we show a subset of RP muta-tions in Prp8 also cause defects in the transition between the 1st and 2nd catalytic steps of splic-ing. Though Prp8-RP mutants do not cause defects in splicing fidelity, they result in an overall decrease in splicing efficiency. Furthermore, genetic analyses link Snu114 GTP/GDP occupancy to Prp8-dependent regulation of Brr2. Our results implicate the transition between the 1st and 2nd catalytic steps as a critical place in the splicing cycle where Prp8-RP mutants influence splic-ing efficiency. The location of the Prp8-RP mutants, at the “hinge” that links the Prp8 Jab1-MPN regulatory “tail” to the globular portion of the domain, suggests that these Prp8-RP mutants inhibit regulated movement of the Prp8 Jab1/MPN domain into the Brr2 RNA binding channel to transiently inhibit Brr2 activity. Therefore, in Prp8-linked RP, disease likely results not only from defects in spliceosome assembly and activation, but also because of defects in splicing ca-talysis. paper to be submitted
2016-07-21 | GSE75081 | GEO
Project description:The essential process of pre-mRNA splicing must occur with high fidelity and efficiency for proper gene expression. The spliceosome employs DExD/H box helicases to promote on-pathway interactions while simultaneously minimizing errors. Prp8 and Snu114, an EF2-like GTPase, regulate the activity of the Brr2 helicase, promoting RNA unwinding by Brr2 at appro-priate points in the splicing cycle and repressing it at others. Mutations linked to Retinitis Pig-mentosa (RP), a disease that causes blindness in humans, map to the Brr2 regulatory region of Prp8. Previous In vitro studies of homologous mutations in Saccharomyces cerevisiae show that Prp8-RP mutants cause defects in spliceosome activation. Here we show a subset of RP muta-tions in Prp8 also cause defects in the transition between the 1st and 2nd catalytic steps of splic-ing. Though Prp8-RP mutants do not cause defects in splicing fidelity, they result in an overall decrease in splicing efficiency. Furthermore, genetic analyses link Snu114 GTP/GDP occupancy to Prp8-dependent regulation of Brr2. Our results implicate the transition between the 1st and 2nd catalytic steps as a critical place in the splicing cycle where Prp8-RP mutants influence splic-ing efficiency. The location of the Prp8-RP mutants, at the â??hingeâ?? that links the Prp8 Jab1-MPN regulatory â??tailâ?? to the globular portion of the domain, suggests that these Prp8-RP mutants inhibit regulated movement of the Prp8 Jab1/MPN domain into the Brr2 RNA binding channel to transiently inhibit Brr2 activity. Therefore, in Prp8-linked RP, disease likely results not only from defects in spliceosome assembly and activation, but also because of defects in splicing ca-talysis. paper to be submitted Two channel microarrays were used. RNA isolated from wt yeast grown simultaneously to the mutant was used as a reference. This reference was used in one of the channels for each hybridization and used in the statistical analysis to obtain an average expression-profile for each mutant relative to the wt. Three independent cultures were hybridized on two separate microarrays. For the first hybridization the Cy5 (red) labeled cRNA from the mutant is hybridized together with the Cy3 (green) labeled cRNA from the common reference. For the replicate hybridization, the labels are swapped. Each gene is represented twice on the microarray, resulting in four measurements per mutant. Strains, both WT and mutant, were grown at 37C until mid-log phase, OD600 of approximately 0.7. The mutated PRP8 gene is present on HIS marked CEN plasmid, and the corresponding genomic copy of PRP8 deleted. Strains labeled as wildtype also have the relevant genomic PRP8 deleted, but complemented with wildtype PRP8 on CEN plasmid.
2016-07-21 | E-GEOD-75081 | biostudies-arrayexpress
Project description:Purpose: To assess the global impacts of RNaseH domain alleles of Prp8 on the in vivo splice site selection for native introns. Conclusions: Our study reveals functional links between distinct spliceosomal conformations and splicing fidelity.
2017-06-21 | GSE96891 | GEO
Project description:Brr2 is a DExD/H-box helicase responsible for U4/U6 unwinding, a critical step in spliceosomal activation. Brr2 contains an N-terminal domain and two tandem sets of a helicase-like domain followed by a Sec63 domain with unknown function. We determined the crystal structure of the second Sec63 domain, which unexpectedly resembles domains 4 and 5 of DNA helicase Hel308. The helicase-like domain upstream of Sec63 has clear sequence similarity with domains 1-3 of Hel308. In addition modeling indicates that Brr2 is composed of an N-terminal domain and two consecutive Hel308-like modules (Hel308-I and II). Together this provides our first glimpse of the overall structure of this large and unique spliceosomal ATPase and helicase. Our structural model and mutagenesis data suggest that Brr2 shares a similar helicase mechanism to Hel308, that differs from many DEAD-box proteins. We demonstrate that Hel308-II interacts with Prp8 and Snu114 in vitro and in vivo, potentially serving as a mediator for the regulation of Brr2â??s activity by Prp8. We further find that the C-terminal region of Prp8 (Prp8-CTR) facilitates the binding of the Brr2/Prp8-CTR complex to U4/U6, suggesting a potential role of Prp8-CTR as an auxiliary substrate binding and specificity domain for Brr2. Splicing specific microarrays were used to assess the genome-wide defects in pre-mRNA splicing that result from a deletion of the second Sec63 domain of yeast Brr2.
2010-05-18 | E-GEOD-16135 | biostudies-arrayexpress
Project description:The spliceosome undergoes extensive rearrangements as it assembles in multiple steps onto the precursor messenger RNA. In the earliest assembly step, U1snRNA identifies the 5' splice site through base-pairing interactions. However, U1snRNA leaves the spliceosome relatively early in the assembly process. The 5' splice site identity is subsequently maintained through interactions with U6snRNA, protein factor PRP8, and other components of the spliceosome during the complex assembly and rearrangements that build the catalytic site. Using a forward genetic screen in C. elegans, we have identified splicing suppressors of a locomotion defect caused by a 5'ss mutation. Here we report three new extragenic suppressor alleles from this screen, two in PRP8 and one in SNRNP200/Brr2. mRNASeq studies of these suppressor strains indicates that there are specific native targets with alternative 5' and alternative 3' splicing events affected by these suppressors, especially for the suppressor PRP8 D 1549N (position D1556 in humans). The strong suppressor at the unstructured N-terminus of SNRP200, N18K, indicates a potential regulatory role for this region. By examining distinct changes in the splicing of native genes, and by mapping these conserved suppressor residues onto cryoEM structural models of assembling human spliceosomes, we conclude that there are multiple interactions in the spliceosome that are required to ensure that the initial 5'ss identified by U1snRNA early in spliceosome assembly is the one that gets loaded into the catalytic core.The spliceosome undergoes extensive rearrangements as it assembles in multiple steps onto the precursor messenger RNA. In the earliest assembly step, U1snRNA identifies the 5' splice site through base-pairing interactions. However, U1snRNA leaves the spliceosome relatively early in the assembly process. The 5' splice site identity is subsequently maintained through interactions with U6snRNA, protein factor PRP8, and other components of the spliceosome during the complex assembly and rearrangements that build the catalytic site. Using a forward genetic screen in C. elegans, we have identified splicing suppressors of a locomotion defect caused by a 5'ss mutation. Here we report three new extragenic suppressor alleles from this screen, two in PRP8 and one in SNRNP200/Brr2. mRNASeq studies of these suppressor strains indicates that there are specific native targets with alternative 5' and alternative 3' splicing events affected by these suppressors, especially for the suppressor PRP8 D 1549N (position D1556 in humans). The strong suppressor at the unstructured N-terminus of SNRP200, N18K, indicates a potential regulatory role for this region. By examining distinct changes in the splicing of native genes, and by mapping these conserved suppressor residues onto cryoEM structural models of assembling human spliceosomes, we conclude that there are multiple interactions in the spliceosome that are required to ensure that the initial 5'ss identified by U1snRNA early in spliceosome assembly is the one that gets loaded into the catalytic core.
2021-11-23 | GSE189437 | GEO
Project description:Brr2 is a DExD/H-box helicase responsible for U4/U6 unwinding, a critical step in spliceosomal activation. Brr2 contains an N-terminal domain and two tandem sets of a helicase-like domain followed by a Sec63 domain with unknown function. We determined the crystal structure of the second Sec63 domain, which unexpectedly resembles domains 4 and 5 of DNA helicase Hel308. The helicase-like domain upstream of Sec63 has clear sequence similarity with domains 1-3 of Hel308. In addition modeling indicates that Brr2 is composed of an N-terminal domain and two consecutive Hel308-like modules (Hel308-I and II). Together this provides our first glimpse of the overall structure of this large and unique spliceosomal ATPase and helicase. Our structural model and mutagenesis data suggest that Brr2 shares a similar helicase mechanism to Hel308, that differs from many DEAD-box proteins. We demonstrate that Hel308-II interacts with Prp8 and Snu114 in vitro and in vivo, potentially serving as a mediator for the regulation of Brr2’s activity by Prp8. We further find that the C-terminal region of Prp8 (Prp8-CTR) facilitates the binding of the Brr2/Prp8-CTR complex to U4/U6, suggesting a potential role of Prp8-CTR as an auxiliary substrate binding and specificity domain for Brr2.
2009-05-20 | GSE16135 | GEO
Project description:Pre-mRNA splicing catalyzed by the spliceosome represents a critical step in the regulation of gene expression contributing to transcriptome and proteome diversity. The spliceosome consists of five small nuclear ribonucleoprotein particles (snRNPs) biogenesis of which remains only partially understood. Here we define the evolutionarily conserved protein Ecdysoneless (Ecd) as a critical regulator of U5 snRNP assembly and Prp8 stability. Combining Drosophila genetics with proteomic approaches we demonstrate Ecd requirement for the maintenance of adult healthspan and lifespan and identify the Sm ring protein SmD3 as a novel interaction partner of Ecd. We show that the predominant task of Ecd is to deliver Prp8 to the Sm protein ring within emerging U5 snRNPs. Ecd deficiency leads to reduced Prp8 protein levels and compromised U5 snRNP biogenesis, causing loss of splicing fidelity and transcriptome integrity. Based on our findings, we propose that Ecd acts as a chaperone that delivers Prp8 to the forming U5 snRNP allowing completion of the cytoplasmic part of the U5 snRNP biogenesis necessary to meet the demand of cells for functional spliceosomes.
2021-04-21 | GSE149056 | GEO
Project description:DEAD-box proteins, a family of RNA-dependent ATPases, promote the numerous conformational rearrangements required for spliceosome assembly, activation, and disassembly. Previous work showed that a cold-sensitive substitution in DEAD-box protein Prp28 prevents the switch from U1 to U6 snRNA pairing with the 5’ splice site. Little is known about how Prp28 is regulated, although U5 snRNP protein Prp8 is a potential coordinator of Prp28 and other spliceosomal ATPases. We conducted a targeted selection in Prp8 for cold-insensitive suppressors of prp28-1, then used splicing specific microarrays to assess suppression of the prp28-1 splicing defect. Splicing specific microarrays were used to assess suppression of the prp28-1 splicing defect by a prp8 allele (prp8-tes) that suppresses prp28-1 cold-sensitivity
2014-01-01 | E-GEOD-42754 | biostudies-arrayexpress
Project description:The functional consequences for alternative splicing of altering the transcription rate have been the subject of intensive study in mammalian cells but less is known about effects on splicing of changing the transcription rate in yeast. We present several lines of evidence showing that slow RNA polymerase II elongation increases both co-transcriptional splicing and splicing efficiency and faster elongation reduces co transcriptional splicing and splicing efficiency in budding yeast, suggesting that splicing is more efficient when co-transcriptional. Moreover, we demonstrate that altering RNA polymerase II elongation rate in either direction compromises splicing fidelity, and we reveal that splicing fidelity depends largely on intron length together with secondary structure and splice site score. These effects are notably stronger for the highly expressed ribosomal protein coding transcripts. We propose that transcription by RNA polymerase II is tuned to optimise the efficiency and accuracy of ribosomal protein gene expression, while allowing flexibility in splice site choice with the nonribosomal protein transcripts.
2017-11-25 | GSE99161 | GEO
Project description:Proteins containing DZF (domain associated with zinc fingers) modules play important roles throughout gene expression, from transcription to translation. Derived from nucleotidyltransferases but lacking catalytic residues, DZF domains serve as heterodimerization surfaces between DZF protein pairs. Three DZF proteins are widely expressed in mammalian tissues, ILF2, ILF3, and ZFR, which form mutually exclusive ILF2-ILF3 and ILF2-ZFR heterodimers. Using eCLIP-Seq, we find that ZFR binds across broad intronic regions to regulate the alternative splicing of cassette and mutually exclusive exons. ZFR preferentially binds dsRNA in vitro and is enriched on introns containing conserved dsRNA elements in cells. Many splicing events are similarly altered upon depletion of any of the three DZF proteins; however, we also identify independent and opposing roles for ZFR and ILF3 in alternative splicing regulation. Along with widespread involvement in cassette exon splicing, the DZF proteins control the fidelity and regulation of over a dozen highly validated mutually exclusive splicing events. Our findings indicate that the DZF protein complexes form a complex regulatory network that leverages dsRNA binding by ILF3 and ZFR to modulate splicing regulation and fidelity.
2023-05-09 | GSE206059 | GEO