Loop I of U1 small nuclear RNA is the only essential RNA sequence for binding of specific U1 small nuclear ribonucleoprotein particle proteins.
The binding of the U1 small nuclear ribonucleoprotein (snRNP)-specific proteins C, A, and 70K to U1 small nuclear RNA (snRNA) was analyzed. Assembly of U1 snRNAs from bean and soybean and a set of mutant Xenopus U1 snRNAs into U1 snRNPs in Xenopus egg extracts was studied. The ability to bind proteins was analyzed by immunoprecipitation with monospecific antibodies and by a protein-sequestering assay. The only sequence essential for binding of the U1-specific proteins was the conserved loop sequence in the 5' hairpin of U1. Further analysis suggested that protein C binds directly to the loop and that the assembly of proteins A and 70K into the RNP requires mainly protein-protein interactions. Protein C apparently recognizes a specific RNA sequence rather than a secondary structural element in the RNA.
Hamm
J
J
European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
van Santen
V L
VL
Spritz
R A
RA
Mattaj
I W
IW
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D010944:Plants; D011485:Protein Binding; D012342:RNA, Small Nuclear / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D017411:Ribonucleoproteins, Small Nuclear; D013045:Species Specificity; D014982:Xenopus laevis
D012342:RNA, Small Nuclear; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear