A novel SR-related protein is required for the second step of pre-mRNA splicing
A novel SR-related protein is required for the second step of pre-mRNA splicing
复制标题
DOI：
10.1128/mcb.25.8.2969-2980.2005
复制
发表时间：
2005-04-01
影响因子：
5.3
通讯作者：
Cáceres, JF
中科院分区：
文献类型：
--
作者：
Cazalla, D;Newton, K;Cáceres, JF
SR家族蛋白和SR相关多肽是前体mRNA剪接的重要调节因子。一种新的SR相关蛋白的表观分子量为53 kDa的基因陷阱筛选，确定蛋白质定位于核斑点中分离。这种新的蛋白质具有精氨酸和丝氨酸丰富的结构域，并被称为SRrp53（SR相关蛋白的53 kDa）。为了支持这种新型含RS蛋白在前mRNA剪接中的作用，我们鉴定了酿酒酵母U1 snRNP特异性蛋白Luc7 p和U2 AF（65）相关因子HCC 1的小鼠直系同源物作为相互作用蛋白。此外，SRrp53能够在酵母双杂交系统和细胞提取物中与SR蛋白家族的一些成员和U2AF（35）相互作用。我们发现，在HeLa细胞核提取物免疫耗竭SRrp53，前mRNA剪接的第二步被阻断，重组SRrp53能够恢复剪接活性。SRrp53还以浓度依赖性方式调节可变剪接。两者合计，这些结果表明，SRrp53是一种新的SR相关蛋白，具有组成性和选择性剪接的作用。
The SR family proteins and SR-related polypeptides are important regulators of pre-mRNA splicing. A novel SR-related protein of an apparent molecular mass of 53 kDa was isolated in a gene trap screen that identifies proteins which localize to the nuclear speckles. This novel protein possesses an arginine- and serine-rich domain and was termed SRrp53 (for SR-related protein of 53 kDa). In support for a role of this novel RS-containing protein in pre-mRNA splicing, we identified the mouse ortholog of the Saccharomyces cerevisiae U1 snRNP-specific protein Luc7p and the U2AF(65)-related factor HCC1 as interacting proteins. In addition, SRrp53 is able to interact with some members of the SR family of proteins and with U2AF(35) in a yeast two-hybrid system and in cell extracts. We show that in HeLa nuclear extracts immunodepleted of SRrp53, the second step of pre-mRNA splicing is blocked, and recombinant SRrp53 is able to restore splicing activity. SRrp53 also regulates alternative splicing in a concentration-dependent manner. Taken together, these results suggest that SRrp53 is a novel SR-related protein that has a role both in constitutive and in alternative splicing.