U1小核核糖核蛋白特异性蛋白C在细胞核中的积累是由于其在细胞核中的扩散和滞留。

Nuclear accumulation of the U1 snRNP-specific protein C is due to diffusion and retention in the nucleus.

作者信息

Klein Gunnewiek J M, van Aarssen Y, van der Kemp A, Nelissen R, Pruijn G J, van Venrooij W J

机构信息

Department of Biochemistry, University of Nijmegen, Nijmegen, 6500 HB, The Netherlands.

出版信息

Exp Cell Res. 1997 Aug 25;235(1):265-73. doi: 10.1006/excr.1997.3663.

DOI:10.1006/excr.1997.3663

PMID:9281376

Abstract

The U1 small nuclear ribonucleoprotein particle (snRNP) has an important function in the early formation of the spliceosome, the multicomponent complex in which pre-mRNA splicing takes place. The nuclear localization signals of two of the three U1 snRNP-specific proteins, U1-70K and U1A, have been mapped. Both proteins are transported actively to the nucleus. Here we show by microinjection of Xenopus laevis oocytes that the third U1 snRNP-specific protein, U1C, passively enters the nucleus. Furthermore, we show that in both X. laevis oocytes and cultured HeLa cells mutant U1C proteins that are not able to bind to the U1 snRNP do not accumulate in the nucleus, indicating that nuclear accumulation of U1C is due to incorporation of the protein into the U1 snRNP.

摘要

U1小核核糖核蛋白颗粒（snRNP）在剪接体的早期形成过程中具有重要作用，剪接体是进行前体mRNA剪接的多组分复合物。U1 snRNP特异性蛋白中的三种蛋白中的两种，即U1-70K和U1A的核定位信号已被定位。这两种蛋白都能被主动转运到细胞核。在这里，我们通过向非洲爪蟾卵母细胞显微注射发现，第三种U1 snRNP特异性蛋白U1C是被动进入细胞核的。此外，我们还表明，在非洲爪蟾卵母细胞和培养的HeLa细胞中，无法与U1 snRNP结合的突变型U1C蛋白不会在细胞核中积累，这表明U1C在细胞核中的积累是由于该蛋白掺入了U1 snRNP。