SR蛋白家族成员在体内新生和成熟mRNA颗粒的形成过程中表现出多种活性。

SR protein family members display diverse activities in the formation of nascent and mature mRNPs in vivo.

作者信息

Sapra Aparna K, Ankö Minna-Liisa, Grishina Inna, Lorenz Mike, Pabis Marta, Poser Ina, Rollins Jarod, Weiland Eva-Maria, Neugebauer Karla M

机构信息

Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden, Germany.

出版信息

Mol Cell. 2009 Apr 24;34(2):179-90. doi: 10.1016/j.molcel.2009.02.031.

DOI:10.1016/j.molcel.2009.02.031

PMID:19394295

Abstract

The SR proteins are a family of pre-mRNA splicing factors with additional roles in gene regulation. To investigate individual family members in vivo, we generated a comprehensive panel of stable cell lines expressing GFP-tagged SR proteins under endogenous promoter control. Recruitment of SR proteins to nascent FOS RNA was transcription dependent and RNase sensitive, with unique patterns of accumulation along the gene specified by the RNA recognition motifs (RRMs). In addition, all SR protein interactions with Pol II were RNA dependent, indicating that SR proteins are not preassembled with Pol II. SR protein interactions with RNA were confirmed in situ by FRET/FLIM. Interestingly, SC35-GFP also exhibited FRET with DNA and failed to associate with cytoplasmic mRNAs, whereas all other SR proteins underwent nucleocytoplasmic shuttling and associated with specific nuclear and cytoplasmic mRNAs. Because different constellations of SR proteins bound nascent, nuclear, and cytoplasmic mRNAs, mRNP remodeling must occur throughout an mRNA's lifetime.

摘要

SR蛋白是一类前体mRNA剪接因子，在基因调控中还具有其他作用。为了在体内研究单个家族成员，我们构建了一组稳定的细胞系，这些细胞系在内源启动子控制下表达绿色荧光蛋白标记的SR蛋白。SR蛋白募集到新生的FOS RNA上是转录依赖性的且对RNase敏感，沿着由RNA识别基序（RRMs）指定的基因具有独特的积累模式。此外，所有SR蛋白与Pol II的相互作用都是RNA依赖性的，这表明SR蛋白不是与Pol II预先组装在一起的。通过FRET/FLIM在原位证实了SR蛋白与RNA的相互作用。有趣的是，SC35-GFP也与DNA表现出FRET，并且不与细胞质mRNA结合，而所有其他SR蛋白都进行核质穿梭并与特定的核和细胞质mRNA结合。由于不同组合的SR蛋白与新生的、核内的和细胞质的mRNA结合，因此mRNA的重塑必定在其整个生命周期中发生。