A naturally occurring 4-bp deletion in the intron 4 of p53 creates a spectrum of novel p53 isoforms with anti-apoptosis function.

ABSTRACT: p53 functions as a tumor suppressor by transcriptionally regulating the expression of genes involved in controlling cell proliferation or apoptosis. p53 and its isoform ?133p53/?113p53 form a negative regulation loop in that p53 activates the expression of ?133p53/?113p53 while ?133p53/?113p53 specifically antagonizes p53 apoptotic activity. This pathway is especially important to safeguard the process of embryogenesis because sudden activation of p53 by DNA damage signals or developmental stress is detrimental to a developing embryo. Here we report the identification of five novel p53 isoforms. p53? is generated due to alternative splicing of the intron 8 of p53 while the other four, namely, TA2p53, TA3p53, TA4p53 and TA5p53, result from the combination of alternative splicing of intron 1 (within intron 4 of the p53 gene) of the ?113p53 gene and a naturally occurring CATT 4 bp deletion within the alternative splicing product in zebrafish. The CATT 4 bp deletion creates four translation start codons which are in-frame to the open reading frame of ?113p53. We also show that TAp53 shares the same promoter with ?113p53 and functions to antagonize p53 apoptotic activity. The identification of ?113p53/TA2/3/4/5p53 reveals a pro-survival mechanism which operates robustly during embryogenesis in response to the DNA-damage condition.

SUBMITTER: Shi H 

PROVIDER: S-EPMC4333405 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature