Control of transcription by Pontin and Reptin

Zoologisches Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
Trends in cell biology (Impact Factor: 12.31). 05/2007; 17(4):187-92. DOI: 10.1016/j.tcb.2007.02.005
Source: PubMed

ABSTRACT Pontin and Reptin are two closely related members of the AAA+ family of DNA helicases. They have roles in diverse cellular processes, including the response to DNA double-strand breaks and the control of gene expression. The two proteins share residence in different multiprotein complexes, such as the Tip60, Ino80, SRCAP and Uri1 complexes in animals, which are involved (directly or indirectly) in transcriptional regulation, but they also function independently from each other. Both Reptin and Pontin repress certain transcriptional targets of Myc, but only Reptin is required for the repression of specific beta-catenin and nuclear factor-kappaB targets. Here, I review recent studies that have addressed the mechanisms of transcriptional control by Pontin and Reptin.

Download full-text


Available from: Peter Gallant, Aug 17, 2015
  • Source
    • "In this study, we identify RUVBL2 as a novel transcriptional repressor of ARF. It has long been recognized that RUVBL2 and its homolog RUVBL1 are involved in the regulation of transcription [21]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: ARF is the second most commonly inactivated tumor suppressor behind p53. It has been implicated in the control of cell proliferation, cell senescence, and tumor suppression. However, the detailed mechanism underlying the transcriptional control of ARF remains largely unknown. Here we report RUVBL2 as a novel transcriptional repressor of ARF. Ectopic expression of RUVBL2 decreases the levels of ARF, whereas knockdown of RUVBL2 results in a marked increase in ARF levels. In addition, RUVBL2 down-regulates the levels of p53 in an ARF-dependent manner. Mechanistically, RUVBL2 binds to the distal region of ARF promoter, thus leading to the repression of ARF transcription. These results suggest an important role of RUVBL2 in the regulation of ARF-p53 pathway.
    FEBS letters 02/2012; 586(4):435-41. DOI:10.1016/j.febslet.2012.01.026 · 3.34 Impact Factor
  • Source
    • "Very recently, pontin and reptin, two highly conserved members of the AAA+ family of ATPases (putative DNA helicases), initially named RUVBL1 and RUVBL2 after the bacterial RuvB-Hollidayjunction migrating helicase, were found to associate with both subunits of human telomerase [8]. In both S. cerevisiae and humans, Rvb1/pontin and Rvb2/reptin are parts of several complexes involved in chromatin modification and also play major roles in the regulation of transcription [9] [10] [11] [12]. In S. cerevisiae, there has been so far no interaction, physical, genetic or other between Rvb1 or Rvb2 and telomerase reported in the literature. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Telomerase is a reverse transcriptase that maintains linear telomeres at a constant length. Here, we report that in the budding yeast Saccharomyces cerevisiae, Rvb2, a highly conserved member of the AAA+ family of ATPases, physically associates with telomerase/Est2 in vivo, both expressed from their endogenous promoter. Importantly, in genetic settings leading to a failure to recruit telomerase at telomeric ends, Rvb2 still associated with Est2. On the other hand, Rvb2 was present in immunoprecipitates of crosslinked telomeric chromatin even in the presumed absence of telomerase at the telomeres. Finally, we could also isolate RVB2 mutant alleles conferring slight, but stable, telomere shortening.
    FEBS letters 11/2011; 585(24):3890-7. DOI:10.1016/j.febslet.2011.11.013 · 3.34 Impact Factor
  • Source
    • "It was hypothesized that the interaction with MLA leads to derepression of basal resistance signaling. Finally, even N-terminal domains of the plasma membrane–associated CC-NB- LRR protein RPM1 were shown to interact with TIP49a, a nuclear factor involved in the transcriptional machinery and chromatin remodeling (Holt et al., 2002; Gallant, 2007). Hence, it is tempting to infer from these examples that the nuclear localization of Rx1 might be similarly linked to transcriptional regulation of downstream signaling pathways, of which the mechanism has not been elucidated yet. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The Rx1 protein, as many resistance proteins of the nucleotide binding-leucine-rich repeat (NB-LRR) class, is predicted to be cytoplasmic because it lacks discernable nuclear targeting signals. Here, we demonstrate that Rx1, which confers extreme resistance to Potato virus X, is located both in the nucleus and cytoplasm. Manipulating the nucleocytoplasmic distribution of Rx1 or its elicitor revealed that Rx1 is activated in the cytoplasm and cannot be activated in the nucleus. The coiled coil (CC) domain was found to be required for accumulation of Rx1 in the nucleus, whereas the LRR domain promoted the localization in the cytoplasm. Analyses of structural subdomains of the CC domain revealed no autonomous signals responsible for active nuclear import. Fluorescence recovery after photobleaching and nuclear fractionation indicated that the CC domain binds transiently to large complexes in the nucleus. Disruption of the Rx1 resistance function and protein conformation by mutating the ATP binding phosphate binding loop in the NB domain, or by silencing the cochaperone SGT1, impaired the accumulation of Rx1 protein in the nucleus, while Rx1 versions lacking the LRR domain were not affected in this respect. Our results support a model in which interdomain interactions and folding states determine the nucleocytoplasmic distribution of Rx1.
    The Plant Cell 12/2010; 22(12):4195-215. DOI:10.1105/tpc.110.077537 · 9.58 Impact Factor
Show more