Open AccessThe U1 small nuclear ribonucleoprotein (snRNP) 70K protein is transported independently of U1 snRNP particles via a nuclear localization signal in the RNA-binding domain.
Author(s) -
Joelle Romac,
D. H. Graff,
Jack D. Keene
Publication year - 1994
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.14.7.4662
Subject(s) - biology , small nuclear ribonucleoprotein , ribonucleoprotein , nls , nuclear localization sequence , snrnp , rna , heterogeneous nuclear ribonucleoprotein , heterogeneous ribonucleoprotein particle , rna recognition motif , rna binding protein , cell nucleus , microbiology and biotechnology , small nuclear rna , nuclear transport , nuclear protein , nucleus , non coding rna , genetics , transcription factor , gene
Expression of the recombinant human U1-70K protein in COS cells resulted in its rapid transport to the nucleus, even when binding to U1 RNA was debilitated. Deletion analysis of the U1-70K protein revealed the existence of two segments of the protein which were independently capable of nuclear localization. One nuclear localization signal (NLS) was mapped within the U1 RNA-binding domain and consists of two typically separated but interdependent elements. The major element of this NLS resides in structural loop 5 between the beta 4 strand and the alpha 2 helix of the folded RNA recognition motif. The C-terminal half of the U1-70K protein which was capable of nuclear entry contains two arginine-rich regions, which suggests the existence of a second NLS. Site-directed mutagenesis of the RNA recognition motif NLS demonstrated that the U1-70K protein can be transported independently of U1 RNA and that its association with the U1 small nuclear ribonucleoprotein particle can occur in the nucleus.