The rate of ribosomal protein gene (rp-gene) transcription in yeast is accurately adjusted to the cellular requirement for ribosomes under various growth conditions. However, the molecular mechanisms underlying this co-ordinated transcriptional control have not yet been elucidated. Transcriptional activation of rp-genes is mediated through two different multifunctional transacting factors, ABF1 and RAP1. In this report, we demonstrate that changes in cellular rp-mRNA levels during varying growth conditions are not parallelled by changes in the in vitro binding capacity of ABF1 or RAP1 for their cognate sequences. In addition, the nutritional upshift response of rp-genes observed after addition of glucose to a culture growing on a non-fermentative carbon source turns out not to be the result of increased expression of the ABF1 and RAP1 genes or of elevated DNA-binding activity of these factors. Therefore, growth rate-dependent transcription regulation of rp-genes is most probably not mediated by changes in the efficiency of binding of ABF1 and RAP1 to the upstream activation sites of these genes, but rather through other alterations in the efficiency of transcription activation. Furthermore, we tested the possibility that cAMP may play a role in elevating rp-gene expression during a nutritional shift-up. We found that the nutritional upshift response occurs normally in several mutants defective in cAMP metabolism.
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http://dx.doi.org/10.1007/BF00281618 | DOI Listing |
J Med Microbiol
October 2024
División de Biología Molecular. IPICYT. Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José, #2055, Col. Lomas 4ª sección. San Luis Potosí, San Luis Potosí 78216, Mexico.
. Adherence is a major virulence trait in that, in many strains, depends on the (epithelial adhesin) genes, which confer the ability to adhere to epithelial and endothelial cells of the host. The genes are generally found at subtelomeric regions, which makes them subject to subtelomeric silencing.
View Article and Find Full Text PDFPLoS One
May 2022
Centre for Bioinformatics and Computational Biology, Stellenbosch University, Stellenbosch, South Africa.
We have performed a comprehensive analysis of the involvement of histone H3 and H4 residues in the regulation of chronological lifespan in yeast and identify four structural groups in the nucleosome that influence lifespan. We also identify residues where substitution with an epigenetic mimic extends lifespan, providing evidence that a simple epigenetic switch, without possible additional background modifications, causes longevity. Residues where substitution result in the most pronounced lifespan extension are all on the exposed face of the nucleosome, with the exception of H3E50, which is present on the lateral surface, between two DNA gyres.
View Article and Find Full Text PDFG3 (Bethesda)
August 2021
Department of Biology, New York University, New York, NY 10003, USA.
During lagging-strand synthesis, strand-displacement synthesis by DNA polymerase delta (Pol ∂), coupled to nucleolytic cleavage of DNA flap structures, produces a nick-translation reaction that replaces the DNA at the 5' end of the preceding Okazaki fragment. Previous work following depletion of DNA ligase I in Saccharomyces cerevisae suggests that DNA-bound proteins, principally nucleosomes and the transcription factors Abf1/Rap1/Reb1, pose a barrier to Pol ∂ synthesis and thereby limit the extent of nick translation in vivo. However, the extended ligase depletion required for these experiments could lead to ongoing, non-physiological nick translation.
View Article and Find Full Text PDFCell Rep
March 2020
Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel. Electronic address:
Genome replication perturbs the DNA regulatory environment by displacing DNA-bound proteins, replacing nucleosomes, and introducing dosage imbalance between regions replicating at different S-phase stages. Recently, we showed that these effects are integrated to maintain transcription homeostasis: replicated genes increase in dosage, but their expression remains stable due to replication-dependent epigenetic changes that suppress transcription. Here, we examine whether reduced transcription from replicated DNA results from limited accessibility to regulatory factors by measuring the time-resolved binding of RNA polymerase II (Pol II) and specific transcription factors (TFs) to DNA during S phase in budding yeast.
View Article and Find Full Text PDFMol Cell
December 2018
Institut Jacques Monod, Centre National de la Recherche Scientifique, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France. Electronic address:
The fidelity of transcription initiation is essential for accurate gene expression, but the determinants of start site selection are not fully understood. Rap1 and other general regulatory factors (GRFs) control the expression of many genes in yeast. We show that depletion of these factors induces widespread ectopic transcription initiation within promoters.
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