Influenza Virus NS1A Binding Protein (IVNS1ABP)

The deduced 619-amino acid protein has a calculated molecular mass of 69.7 kD. NS1BP contains an N-terminal BTB/POZ domain that covers about 120 amino acids, followed by 5 imperfect tandem kelch repeats of 47 to 49 amino acids. Northern blot analysis of HeLa cell mRNA detected an NS1BP transcript of about 3.1 kb. Western blot analysis detected endogenous NS1BP as a protein doublet of about 70 kD in 3 human epithelium-derived cell lines. Immunofluorescence analysis of HeLa cells revealed a punctate nuclear staining pattern that colocalized with the spliceosome assembly factor SC35 (SFRS2) and excluded nucleoli.highest levels in kidney and ovary, followed by brain, liver, testis, heart, lung, and pancreas. Intermediate expression was detected in skeletal muscle and spleen.