Evidence for the existence of two human CYP2E1 cDNAs using different polyadenylation signals.

We have isolated a cDNA (named P450 A) which is a variant of CYP2E1 presenting some differences in the 3' non coding region. Two substitutions and only one polyadenylation signal were detected on P450 A compared to CYP2E1 where there are two. With the aim of studying the frequency of utilization of these polyadenylation signals, probe A and probe J specific for P450 A and CYP2E1, respectively, were hybridized on human hepatic and extra-hepatic cDNA samples. Results indicated that in all tissues tested only P450 A using the first polyadenylation signal was detected. The CYP2E1 cDNA isolated by Song et al could be representative of a transcript either rarely represented among the Caucasian population, or expressed in a particular individual or ethnic population, or rapidly degraded.