Characterization of Human RNA Polymerase III Identifies Orthologues for <i>Saccharomyces cerevisiae</i> RNA Polymerase III Subunits

Hu, Ping; Wu, Si; Sun, Yue; Yuan, Chih-Chi; Kobayashi, Ryûji; Myers, Michael P.; Hernandez, Nouria

doi:10.1128/mcb.22.22.8044-8055.2002

Cited by 75 publications

(67 citation statements)

References 69 publications

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“…In most other eukaryotes, five subunits (RPB5, RPB6, RPB8, RPB10 and RPB12) are shared between all three RNAPs (Geiduschek and Kassavetis, 2001;Hu et al, 2002). However, the TriTryp genomes contain two distinct paralogues of RPB5, RPB6 and RPB10 (Ivens et al, 2005;Kelly et al, 2005;Nguyen et al, 2006), and previous reports in T. brucei indicate that at least the RPB5 and RPB6 isoforms are segregated between RNAP I and RNAP II (Walgraffe et al, 2005;Nguyen et al, 2006;Devaux et al, 2006;Das et al, 2006).…”

Section: Discussionmentioning

confidence: 97%

“…Five subunits (RPB5,RPB6,RPB8,RPB10 and RPB12) are shared between all three RNAPs; two (RPAC1 and RPAC2, also known as AC40 and AC19, respectively) are shared between RNAP I and III, with homologues (RPB3 and RPB11, respectively) in RNAP II; and another five (RPA1/RPB1/RPC1, RPA2/RPB2/RPC2, RPA43/RPB7/RPC8, RPA14/RPB4/RPC9 and RPA12/RPB9/RPC10) are homologous subunits. In addition, two subunits (RPA49 and RPA34) are RNAP I-specific, while five (RPC3, RPC4, RPC5, RPC6 and RPC7) are exclusive to RNAP III (Geiduschek and Kassavetis, 2001;Hu et al, 2002). The five core subunits are homologous to the bacterial β′ (RPB1), β (RPB2), α (RPB3 and RPB11) and ω (RPB6) subunits, and correspond to the archaeal A′+A′′, B′+B′′, D, L and K subunits, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the RNA polymerase II and III complexes in Leishmania major

Martínez‐Calvillo

Saxena

Green

et al. 2007

International Journal for Parasitology

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Transcription of protein-coding genes in Leishmania major and other trypanosomatids differs from that in most eukaryotes and bioinformatic analyses have failed to identify several components of the RNA polymerase (RNAP) complexes. To increase our knowledge about this basic cellular process, we used tandem affinity purification (TAP) to identify subunits of RNAP II and III. Mass spectrometric analysis of the complexes co-purified with TAP-tagged LmRPB2 (encoded by LmjF31.0160) identified seven RNAP II subunits: RPB1, RPB2, RPB3, RPB5, RPB7, RPB10 and RPB11. With the exception of RPB10 and RPB11, and the addition of RPB8, these were also identified using TAP-tagged constructs of one (encoded by LmjF34.0890) of the two LmRPB6 orthologues. The latter experiments also identified the RNAP III subunits RPC1 (C160), RPC2 (C128), RPC3 (C82), RPC4 (C53), RPC5 (C37), RPC6 (C34), RPC9 (C17), RPAC1 (AC40) and RPAC2 (AC19). Significantly, the complexes precipitated by TAP-tagged LmRPB6 did not contain any RNAP I-specific subunits, suggesting that, unlike in other eukaryotes, LmRPB6 is not shared by all three polymerases but is restricted to RNAP II and III, while the LmRPB6z (encoded by LmjF25.0140) isoform is limited to RNAP I. Similarly, we identified peptides from only one (encoded by LmjF18.0780) of the two RPB5 orthologues and one (LmjF13.1120) of the two RPB10 orthologues, suggesting that LmRPB5z (LmjF18.0790) and LmRPB10z (LmjF13.1120) are also restricted to RNAP I. In addition to these RNAP subunits, we also identified a number of other proteins that co-purified with the RNAP II and III complexes, including a potential transcription factor, several histones, an ATPase involved in chromosome segregation, an endonuclease, four helicases, RNA splicing factor PTSR-1, at least two RNA binding proteins and several proteins of unknown function.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Characterization of the RNA polymerase II and III complexes in Leishmania major

Martínez‐Calvillo

Saxena

Green

et al. 2007

International Journal for Parasitology

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“…A database search initially identified a paralogue, RPC32β, of the previously described human Pol III subunit RPC32 (10,11) that is hereafter referred to as RPC32α (Fig. S1).…”

Section: Resultsmentioning

confidence: 99%

Two isoforms of human RNA polymerase III with specific functions in cell growth and transformation

Haurie

Durrieu-Gaillard

Dumay‐Odelot

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

111

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Transcription in eukaryotic nuclei is carried out by DNA-dependent RNA polymerases I, II, and III. Human RNA polymerase III (Pol III) transcribes small untranslated RNAs that include tRNAs, 5S RNA, U6 RNA, and some microRNAs. Increased Pol III transcription has been reported to accompany or cause cell transformation. Here we describe a Pol III subunit (RPC32β) that led to the demonstration of two human Pol III isoforms (Pol IIIα and Pol IIIβ). RPC32β-containing Pol IIIβ is ubiquitously expressed and essential for growth of human cells. RPC32α-containing Pol IIIα is dispensable for cell survival, with expression being restricted to undifferentiated ES cells and to tumor cells. In this regard, and most importantly, suppression of RPC32α expression impedes anchorage-independent growth of HeLa cells, whereas ectopic expression of RPC32α in IMR90 fibroblasts enhances cell transformation and dramatically changes the expression of several tumor-related mRNAs and that of a subset of Pol III RNAs. These results identify a human Pol III isoform and isoform-specific functions in the regulation of cell growth and transformation.T ranscription in eukaryotes is mediated by three nuclear DNAdependent RNA polymerases (Pol I, Pol II, and Pol III) (1, 2). Pol III directs transcription of small noncoding RNAs that are involved in translation, splicing, and other cellular processes. Transcription by Pol III is directed by at least three distinct promoter types. Type 1 (5S RNA) and type 2 [tRNA, Alu RNA, and adenoviral viral-associated (VA) RNA] promoters are internal to the gene. Type 3 (U6 and 7SK RNA) promoters are located 5′ to the transcription initiation site (3). The transcription factors that directly recognize these promoters [type 1 by gene-specific TFIIIA and general initiation factor TFIIIC; type 2 by TFIIIC; and type 3 by gene-specific PSE-binding transcription factor/small nuclear RNA-activating protein complex (PTF/SNAPc)] have been well characterized and shown to recruit general initiation factor TFIIIB to their cognate promoters (reviewed in ref. 4). Overall, the multisubunit compositions of TFIIIC and TFIIIB have been conserved from yeast to human (5, 6), but two distinct isoforms of TFIIIB have been identified in human cells-one (TFIIIB-β) active in transcription of type 1 and type 2 promoters and one (TFIIIB-α) active in transcription of type 3 promoters (7). This functional difference reflects the presence of BRF1 in TFIIIB-β and of its paralogue BRF2 in TFIIIB-α (8, 9).Pol III is highly conserved from yeast to humans and composed of 17 subunits. Of these subunits, five are common to all three polymerases, two are shared by Pol I and Pol III, and five are paralogous to subunits found in Pol I and Pol II. However, five subunits are specific to Pol III without a counterpart in Pol I or Pol II (reviewed in refs. 5 and 10). Three of these five Pol III-specific subunits (RPC32, RPC39, and RPC62) form a dissociable ternary subcomplex that is specifically required for transcription initiation (11). This ternary complex...

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“…Engelke, unpubl. ), in human cell culture ␤-tubulin is one of the few nonsubunit proteins associated with highly purified RNA polymerase III (Hu et al 2002(Hu et al , 2003, and it remains possible that microtubules have a direct effect on tRNA gene positioning.…”

Section: Discussionmentioning

confidence: 99%

Clustering of yeast tRNA genes is mediated by specific association of condensin with tRNA gene transcription complexes

et al. 2008

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The 274 tRNA genes in Saccharomyces cerevisiae are scattered throughout the linear maps of the 16 chromosomes, but the genes are clustered at the nucleolus when compacted in the nucleus. This clustering is dependent on intact nucleolar organization and contributes to tRNA gene-mediated (tgm) silencing of RNA polymerase II transcription near tRNA genes. After examination of the localization mechanism, we find that the chromosome-condensing complex, condensin, is involved in the clustering of tRNA genes. Conditionally defective mutations in all five subunits of condensin, which we confirm is bound to active tRNA genes in the yeast genome, lead to loss of both pol II transcriptional silencing near tRNA genes and nucleolar clustering of the genes. Furthermore, we show that condensin physically associates with a subcomplex of RNA polymerase III transcription factors on the tRNA genes. Clustering of tRNA genes by condensin appears to be a separate mechanism from their nucleolar localization, as microtubule disruption releases tRNA gene clusters from the nucleolus, but does not disperse the clusters. These observations suggest a widespread role for condensin in gene organization and packaging of the interphase yeast nucleus.[Keywords: tRNA gene; condensin; microtubules; nuclear organization; nucleolus] Supplemental material is available at http://www.genesdev.org.

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Characterization of Human RNA Polymerase III Identifies Orthologues for Saccharomyces cerevisiae RNA Polymerase III Subunits

Cited by 75 publications

References 69 publications

Characterization of the RNA polymerase II and III complexes in Leishmania major

Characterization of the RNA polymerase II and III complexes in Leishmania major

Two isoforms of human RNA polymerase III with specific functions in cell growth and transformation

Clustering of yeast tRNA genes is mediated by specific association of condensin with tRNA gene transcription complexes

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