Monoclonal Antibodies to the Mouse p19 Arf Tumor Suppressor Protein

Abstract

The Arf tumor suppressor protein inhibits cell proliferation through both p53-dependent and -independent mechanisms. Two rat monoclonal antibodies raised against a peptide corresponding to amino acids 54–75 of the mouse p19^Arf protein reacted with the native protein expressed in mammalian cells. Neither antibody detected human or golden hamster Arf proteins. The two antibodies, both of IgG2b isotype, are directed to adjacent epitopes contained within residues 54–62 and 62–75, respectively, of the mouse p19^Arf protein, and both were highly efficient in detecting p19^Arf by immunoprecipitation, immunoblotting, and immunofluorescence. One antibody proved useful for immunohistochemical staining of p19^Arf in fixed sections of mouse testes, revealing low levels of protein expression within the nucleoli of spermatogonia. This indicates that these antibodies should be useful in detecting the endogenous p19^Arf protein at specific stages of mouse development and during early stages of tumorigenesis.