Mortillaro M J, Blencowe B J, Wei X, Nakayasu H, Du L, Warren S L, Sharp P A, Berezney R
Department of Biological Sciences, State University of New York at Buffalo 14260, USA.
Proc Natl Acad Sci U S A. 1996 Aug 6;93(16):8253-7. doi: 10.1073/pnas.93.16.8253.
A hyperphosphorylated form of the largest subunit of RNA polymerase II (pol IIo) is associated with the pre-mRNA splicing process. Pol IIo was detected in association with a subset of small nuclear ribonucleoprotein particle and Ser-Arg protein splicing factors and also with pre-mRNA splicing complexes assembled in vitro. A subpopulation of pol IIo was localized to nuclear "speckle" domains enriched in splicing factors, indicating that it may also be associated with RNA processing in vivo. Moreover, pol IIo was retained in a similar pattern following in situ extraction of cells and was quantitatively recovered in the nuclear matrix fraction. The results implicate nuclear matrix-associated hyperphosphorylated pol IIo as a possible link in the coordination of transcription and splicing processes.
RNA聚合酶II（pol IIo）最大亚基的一种高度磷酸化形式与前体mRNA剪接过程相关。已检测到pol IIo与一小部分小核核糖核蛋白颗粒和丝氨酸-精氨酸蛋白剪接因子相关，并且还与体外组装的前体mRNA剪接复合体相关。pol IIo的一个亚群定位于富含剪接因子的核“斑点”结构域，这表明它在体内也可能与RNA加工相关。此外，在细胞原位提取后，pol IIo以类似的模式保留，并在核基质组分中被定量回收。这些结果表明，与核基质相关的高度磷酸化pol IIo可能是转录和剪接过程协调中的一个潜在环节。
