Publications by authors named "Abel Cuevas-Bermudez"

The tripartite interaction between the chromatin remodeler complex RSC, RNA polymerase subunit Rpb5 and prefoldin-like Bud27 is necessary for proper RNA pol II elongation. Indeed lack of Bud27 alters this association and affects transcription elongation. This work investigates the consequences of lack of Bud27 on the chromatin association of RSC and RNA pol II, and on nucleosome positioning.

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Rtr1 is an RNA polymerase II (RNA pol II) CTD-phosphatase that influences gene expression during the transition from transcription initiation to elongation and during transcription termination. Rtr1 interacts with the RNA pol II and this interaction depends on the phosphorylation state of the CTD of Rpb1, which may influence dissociation of the heterodimer Rpb4/7 during transcription. In addition, Rtr1 was proposed as an RNA pol II import factor in RNA pol II biogenesis and participates in mRNA decay by autoregulating the turnover of its own mRNA.

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mRNA homoeostasis is favoured by crosstalk between transcription and degradation machineries. Both the Ccr4-Not and the Xrn1-decaysome complexes have been described to influence transcription. While Ccr4-Not has been shown to directly stimulate transcription elongation, the information available on how Xrn1 influences transcription is scarce and contradictory.

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Article Synopsis
  • Research has focused on how three nuclear RNA polymerases work together to produce ribosome components during ribosome biogenesis.
  • The yeast protein Bud27 interacts with a common subunit of these polymerases, influencing their transcription activities, particularly affecting RNA polymerase I and III, as well as regulating RNA polymerase II's transcription of ribosomal proteins.
  • Bud27's role is crucial for maintaining the balance in ribosome production and is linked to the TOR signaling pathway, as its inactivation affects key processes like the phosphorylation of ribosomal protein S6.
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We have adapted a previous procedure and improved an approach that we named yChEFs (yeast Chromatin Enriched Fractions) for purifying chromatin fractions. This methodology allows the easy, reproducible and scalable recovery of proteins associated with chromatin. By using yChEFs, we bypass subcellular fractionation requirements involved when using zymolyase to obtain the spheroplast, which is employed in many other procedures.

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Co-transcriptional imprinting of mRNA by Rpb4 and Rpb7 subunits of RNA polymerase II (RNAPII) and by the Ccr4-Not complex conditions its post-transcriptional fate. In turn, mRNA degradation factors like Xrn1 are able to influence RNAPII-dependent transcription, making a feedback loop that contributes to mRNA homeostasis. In this work, we have used repressible yeast GAL genes to perform accurate measurements of transcription and mRNA degradation in a set of mutants.

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Article Synopsis
  • Bud27 and its human counterpart, URI, belong to the prefoldin family of molecular chaperones, acting as scaffold proteins for RNA polymerase assembly.
  • Unlike typical prefoldins, Bud27 and URI have distinct functions and do not form part of the canonical PFD/GimC complex, suggesting unique roles in different organisms.
  • The interaction profiles of Bud27 indicate significant variations in prefoldin-like complex compositions across species, raising questions about the necessity of Bud27’s interactions with other complexes for its cellular roles.
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Bud27, the yeast orthologue of human URI/RMP, is a member of the prefoldin-like family of ATP-independent molecular chaperones. It has recently been shown to mediate the assembly of the three RNA polymerases in an Rpb5-dependent manner. In this work, we present evidence of Bud27 modulating RNA pol II transcription elongation.

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