Identification of a novel, transactivation-defective splicing variant of p53 gene in patients with chronic lymphocytic leukemia.

p53 is implemented in many processes controlling cell fate. Recently it has been reported that besides post-translational modifications and regulation of protein-protein interactions, the activity of p53 is also substantially controlled at transcriptional level. In 109 out of 127 (86%) patients with chronic lymphocytic leukemia (CLL) we have identified a novel p53 splicing variant, lacking the whole coding sequence of exon 6. This splicing p53 isoform ("delta ex6") is devoid of transactivational activity and is differentially expressed in CLL patients as compared to healthy controls. The overexpression of "delta ex6" p53 variant in CLL patients supports the recent evidence on dysregulation of p53 splicing pattern in malignancies.