 While both CUL4A and CUL4B are expressed in male gametes, CUL4A is highly expressed in pachytenes and diplotenes.It is at these stages that CUL4A-deficient male germ cells exhibit high levels of apoptosis, improper DNA repair and accumulation of the CRL4 substrate Cdt1.The chromosomal region ch13q34 which contains the "CUL4A" gene is amplified in 3-6% of certain carcinomas including