p73, unlike p53, is expressed as a number of isomeric forms. Alternative 
splicing at the 3' end of p73 transcript, together with the usage of a second 
promoter downstream of exon 3, can generate up to 24 p73 isoforms. Variants 
lacking the TA domain (DeltaN isoforms) are induced by TAp73 and by p53, and 
inhibit their transcriptional activity. However, understanding the complex 
biology of p73 has been handicapped by the lack of high affinity specific 
antibodies for the different isoforms. Here, we report the characterization, by 
Western blotting and immunoprecipitation, of three new polyclonal antisera 
recognizing all p73 isoforms, only DeltaN isoforms or only p73alpha, and which 
have advantages of affinity and specificity over previously available 
antibodies.