N. Kataoka et al., Pre-mRNA splicing imprints mRNA in the nucleus with a novel RNA-binding protein that persists in the cytoplasm, MOL CELL, 6(3), 2000, pp. 673-682
We describe a novel RNA binding protein, Y14, a predominantly nuclear nucle
ocytoplasmic shuttling protein. Interestingly, Y14 associates preferentiall
y with mRNAs produced by splicing but not with pre-mRNAs, introns, or mRNAs
produced from intronless cDNAs. Y14 associates with both nuclear mRNAs and
newly exported cytoplasmic mRNAs. Splicing of a single intron is sufficien
t for Y14 association. Y14-containing nuclear complexes are different from
general hnRNP complexes. They contain hnRNP proteins and several unique pro
teins including the mRNA export factor TAP. Thus, Y14 defines novel interme
diates in the pathway of gene expression, postsplicing nuclear preexport mR
NPs, and newly exported cytoplasmic mRNPs, whose composition is established
by splicing. These findings suggest that pre-mRNA splicing imprints mRNA w
ith a unique set of proteins that persists in the cytoplasm and thereby com
municates the history of the transcript.