alternative splicing; 3 kb mRNA complete cds; coding sequence: CDS 86..2209

707-712 amino acids; 76 kDa; N-term proline/glutamine rich domain, a prolin rich region, 2 tandem RNA binding domains, and C-term.

nucleus

splicing factor required early in spliceosome formation; form a complex with the polypyrimidine tract binding protein (PTB, herein the name); involved in pre-m RNA splicing step 2 (step 1: cut after exon n, intron n is still joined to exon n+1; step 2: cut between intron n and exon n+1, join exons n and n+1); forms a heterodimer with p54nrb (nuclear RNA binbing) a protein sharing vast homologies, encoded by NONO; both form complexes with DNA topoisomerase I, which renders this enzyme much more active.

with the above mentioned NONE product and with other proteins with a DBHS domain (Drosophila behaviour, human splicing) which includes the tandem RNA binding domains.