"Pre-mRNA Splicing Imprints mRNA in the Nucleus with a Novel RNA-Binding Protein that Persists in the Cytoplasm".

Naoyuki Kataoka¹, Jeongsik Yong¹, V. Narry Kim¹, Francisco Velazquez¹, Robert A. Perkinson¹, Fan Wang¹, and Gideon Dreyfuss^1
1 Howard Hughes Medical Institute, and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104

Corresponding author: Gideon Dreyfuss¹, 215-898-0398 (phone), 215-573-2000 (fax),
E-mail: gdreyfuss@hhmi.upenn.edu

We describe a novel RNA binding protein, Y14, a predominantly nuclear nucleo-cytoplasmic shuttling protein. Interestingly, Y14 associates preferentially 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 sufficient for Y14 association. Y14-containing nuclear complexes are different from general hnRNP complexes. They contain hnRNP proteins and several unique proteins including the mRNA export factor TAP. Thus, Y14 defines novel intermediates in the pathway of gene expression, post-splicing nuclear pre-export mRNPs, and newly exported cytoplasmic mRNPs, whose composition is established by splicing. These findings suggest that pre-mRNA splicing imprints mRNA with a unique set of proteins that persists in the cytoplasm and thereby communicates the history of the transcript.

1. "Metabolism and Morphology of Ribonucleoprotein Particles from the Cell Nucleus of Lymphocytes".

2. "In-Vitro Incorporation of Amino Acids into the Proteins of Isolated Nuclear Ribosomes".