Component of the spliceosomal U1 snRNP, which is essential for recognition of the pre-mRNA 5' splice-site and the subsequent assembly of the spliceosome (, ). SNRNP70 binds to the loop I region of U1-snRNA ( ).
Truncated isoforms that lack the RRM domain cannot bind U1-snRNA.
Truncated isoforms that lack the RRM domain cannot bind U1-snRNA.
Subcellular locations: Nucleus speckle, Nucleus, Nucleoplasm
Colocalizes with SCNM1 and LUC7L2 in nuclear speckles.