Efficient RNA Polyuridylation by Noncanonical Poly(A) Polymerases (original) (raw)

Ubiquitin-mediated Regulation of RNA Polymerase I in Saccharomyces cerevisiae

2019

Ubiquitin-mediated Regulation of RNA Polymerase I in Saccharomyces cerevisiae Sabrina Kamran Chair of the Supervisory Committee: Associate Professor, Richard G. Gardner Department of Pharmacology Ribosomes are key cellular components ensuring that cells correctly synthesize their protein cohort. Dysregulation of this process can lead to improper cell growth and is linked to the progression of several types of cancers, making understanding of this process of great interest to both researchers and clinicians. Ribosome biogenesis, the process by which ribosomes are produced, is largely controlled by regulating the rate-limiting step of rDNA transcription by RNA Polymerase I, which transcribes three of the four ribosomal RNAs within the cell. Although rDNA transcription is highly regulated by post-translational modifications in response to changing environmental conditions, little is known of how RNA Polymerase I activity is regulated. Our previous research identified a novel role for u...

Termination and pausing of RNA polymerase II downstream of yeast polyadenylation sites

Molecular and Cellular Biology, 1993

Little is known about the transcriptional events which occur downstream of polyadenylation sites. Although the polyadenylation site of a gene can be easily identified, it has been difficult to determine the site of transcription termination in vivo because of the rapid processing of pre-mRNAs. Using an in vitro approach, we have shown that sequences from the 3' ends of two different Saccharomyces cerevisiae genes, ADH2 and GAL7, direct transcription termination and/or polymerase pausing in yeast nuclear extracts. In the case of the ADH2 sequence, the RNA synthesized in vitro ends approximately 50 to 150 nucleotides downstream of the poly(A) site. This RNA is not polyadenylated and may represent the primary transcript. A similarly sized nonpolyadenylated [poly(A)-] transcript can be detected in vivo from the same transcriptional template. A GAL7 template also directs the in vitro synthesis of an RNA which extends a short distance past the poly(A) site. However, a significant amou...

Requirement of Fission Yeast Cid14 in Polyadenylation of rRNAs

Molecular and Cellular Biology, 2006

Polyadenylation in eukaryotes is conventionally associated with increased nuclear export, translation, and stability of mRNAs. In contrast, recent studies suggest that the Trf4 and Trf5 proteins, members of a widespread family of noncanonical poly(A) polymerases, share an essential function in Saccharomyces cerevisiae that involves polyadenylation of nuclear RNAs as part of a pathway of exosome-mediated RNA turnover. Substrates for this