Although yeast RNA polymerase III (Pol III) and the auxiliary factors TFIIIC and TFIIIB are well characterized, the mechanisms of class III gene regulation are poorly understood. Previous studies identified MAF1, a gene that affects tRNA suppressor efficiency and interacts genetically with Pol III. We show here that tRNA levels are elevated in maf1 mutant cells. In keeping with the higher level...

We have examined the influence of RNA upon the interaction of Gag-Pol with Gag during human immunodeficiency virus type 1 (HIV-1) assembly. COS7 cells were transfected with protease-negative HIV-1 proviral DNA, and Gag/Gag-Pol complexes were detected by coimmunoprecipitation with anti-integrase. In COS7 cells, Gag/Gag-Pol is found almost entirely in pelletable, membrane-bound complexes. Exposur...

RNA polymerase III (Pol III) synthesizes short noncoding RNAs, many of which are essential for translation. Accordingly, Pol III activity is tightly regulated with cell growth and proliferation by factors such as MYC, RB1, TRP53, and MAF1. MAF1 is a repressor of Pol III transcription whose activity is controlled by phosphorylation; in particular, it is inactivated through phosphorylation by the...

During herpes simplex virus infection, expression of the viral DNA polymerase (pol) gene is regulated temporally as an early (beta) gene and is additionally down-regulated at late times at the level of translation (D. R. Yager, A. I. Marcy, and D. M. Coen, J. Virol. 64:2217-2225, 1990). To examine the role of viral DNA synthesis in pol regulation, we studied pol expression during infections in ...

Live cell imaging of mammalian RNA polymerase II (Pol II) has previously relied on random insertions of exogenous, mutant Pol II coupled with the degradation of endogenous Pol II using a toxin, α-amanitin. Therefore, it has been unclear whether over-expression of labeled Pol II under an exogenous promoter may have played a role in reported Pol II dynamics in vivo. Here we label the endogenous P...

Our view of the RNA polymerase III (Pol III) transcription machinery in mammalian cells arises mostly from studies of the RN5S (5S) gene, the Ad2 VAI gene, and the RNU6 (U6) gene, as paradigms for genes with type 1, 2, and 3 promoters. Recruitment of Pol III onto these genes requires prior binding of well-characterized transcription factors. Technical limitations in dealing with repeated genomi...

The determinants critical for the incorporation of Pr160(gag-pol) into human immunodeficiency virus type 1 (HIV-1) particles were examined by cotransfecting cells with (i) a plasmid expressing wild-type Gag protein and (ii) a series of chimeric Gag-Pol expression plasmids in which individual murine leukemia virus (MLV) Gag regions and subdomains precisely replaced their HIV-1 counterparts. The ...

RNA polymerase I (Pol I) produces large ribosomal RNAs (rRNAs). In this study, we show that the Rpa49 and Rpa34 Pol I subunits, which do not have counterparts in Pol II and Pol III complexes, are functionally conserved using heterospecific complementation of the human and Schizosaccharomyces pombe orthologues in Saccharomyces cerevisiae. Deletion of RPA49 leads to the disappearance of nucleolar...

DNA polymerase eta (Pol eta) is a member of the mammalian Y family polymerases and performs error-free translesion synthesis across UV-damaged DNA. For this function, Pol eta accumulates in nuclear foci at replication stalling sites via its interaction with monoubiquitinated PCNA. However, little is known about the posttranslational control mechanisms of Pol eta, which regulate its accumulation...

Biochemical probes positioned on the surface of the general transcription factor TFIIB were used to probe the architecture of the RNA polymerase II (Pol II) transcription preinitiation complex (PIC). In PICs, the TFIIB linker and core domains are positioned over the central cleft and wall of Pol II. This positioning is not observed in the smaller Pol II-TFIIB complex. These results lead to a ne...