Vol. 29, Issue 1, 4-7, January 2001

SHORT COMMUNICATION
Identification of a New Human CYP2A Gene Fragment with Close Linkage to CYP2GP1

Jiangjun Sheng, Zichun Hua, Jiancheng Guo, Michele Caggana, and Xinxin Ding

Wadsworth Center, New York
State Department of Health
(J.S., Z.H., J.G., M.C., X.D.)
School of Public Health, State
University of New York at Albany
Albany, NY (J.S., M.C., X.D.); and
Pharmaceutical Biotechnology
Laboratory, Department of Biochemistry
Nanjing University, Nanjing, China (Z.H.)

Human genomic libraries were screened to identify CYP2G-related cytochrome P450 genes. A genomic fragment comprising exons 7 through 9 of CYP2GP1 and exons 6 through 9 of a previously unidentified CYP2A gene, designated CYP2A7P2, was isolated from an EMBL3 library; the two genes were arranged in outward opposite directions with about 8 kbp of intervening sequence. The same structure was also detected in a bacteriophage P1 clone, which contained a full-length CYP2GP1 gene, exons 6 through 9 of CYP2A7P2, and the CYP2B7 gene. However, additional CYP2A-related exons as well as other CYP2A genes, CYP2A7P1, CYP2B6, CYP2F1, and CYP2GP2 were not detected. These results indicate that CYP2A7P2 is located near CYP2B7 in the middle of the CYP2A-2B-2F gene cluster on chromosome 19. Furthermore, an analysis of CYP2A sequence alignment suggests that CYP2A7P2 may be derived from the same ancestral gene that gave rise to CYP2A7P1, which was corrupted by a large insertion at intron 5.