Argasinska Joanna, Zhou Kai, Donnelly Robert J, Hay Ronald T, Lee Chee-Gun
Department of Biochemistry and Molecular Biology, Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, 185 South Orange Avenue, Newark, NJ 07103, USA.
J Mol Biol. 2004 Jul 30;341(1):15-25. doi: 10.1016/j.jmb.2004.06.004.
RNA helicase A (RHA) is a member of the DEAH helicase family of proteins. Recent studies imply the role of RHA in the regulation of the topology of chromatin DNA, which could influence diverse nuclear processes such as transcription activity of the chromatin DNA and chromosome condensation. We previously reported that Ubc9, an E2-like enzyme specific for small ubiquitin-like modifier 1 (Sumo-1), is required for the interaction between RHA and topoisomerase IIalpha. Here, we describe that Ubc9 is a novel factor that functionally interacts with RHA and activates the transcription activity of RHA, measured in the CREB-mediated pathway. We demonstrate that the N-terminal domain of RHA, encompassing amino acid residues 1-137, is sufficient for its interaction with Ubc9. Our data also show that interaction with Ubc9 leads to the Sumo-1 conjugation of RHA both in vitro and in vivo. However, the catalytic activity of Ubc9 seems to be dispensable for the transcription activation activity of RHA. Our observation suggests multiple roles for Ubc9 in the regulation of the RHA function.
RNA解旋酶A（RHA）是DEAH解旋酶蛋白家族的成员。最近的研究表明RHA在染色质DNA拓扑结构的调控中发挥作用，这可能会影响多种核过程，如染色质DNA的转录活性和染色体凝聚。我们之前报道过，泛素结合酶9（Ubc9）是一种特异性针对小泛素样修饰物1（Sumo-1）的类E2酶，它是RHA与拓扑异构酶IIα相互作用所必需的。在此，我们描述了Ubc9是一种与RHA发生功能相互作用并激活RHA转录活性的新因子，这是在CREB介导的途径中测得的。我们证明，RHA的N端结构域，包含氨基酸残基1至137，足以使其与Ubc9相互作用。我们的数据还表明，与Ubc9的相互作用在体外和体内都会导致RHA的Sumo-1缀合。然而，Ubc9的催化活性似乎对于RHA的转录激活活性是可有可无的。我们的观察结果表明Ubc9在RHA功能调控中具有多种作用。
