Author(s): Bhaskaran A, May D, RandWeaver M, Tyler CR
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Abstract The p53 gene is believed to be mutated or deficient in over 50\% of human tumours, and is therefore considered to be instrumental in the process of carcinogenesis. Recently in humans, homologues of p53 (such as p73 and p63) have been isolated. In our studies in fish, we have been isolating tumour suppressor genes with a view to their potential use to study genotoxins in the aquatic environment. In this paper, we report the characterisation of the first non-mammalian p73 cDNA, isolated from barbel (Barbus barbus), a freshwater cyprinid fish indigenous to UK rivers. The deduced barbel p73 amino acid sequence has a high homology with human p73 alpha: the proteins are 641 and 636 aa in length, respectively, and there is a 72\% identity over the entire sequence length of the protein (over 90\% in the putative DNA binding domain). The level of conservancy for p73 is considerably higher across class (from man to fish), than for p53 and it may therefore have particular value in studies on environmental mutagenesis. Northern analysis showed expression of three p73 mRNA transcripts/homologues. The patterns of p73 tissue expression in the barbel differed from the expression of p53 mRNA, suggesting specific functional roles for the two genes.
This article was published in Comp Biochem Physiol B Biochem Mol Biol
and referenced in Fisheries and Aquaculture Journal