THE HUMAN SEROTONIN N-ACETYLTRANSFERASE (EC-2.3.1.87) GENE (AANAT) - STRUCTURE, CHROMOSOMAL LOCALIZATION, AND TISSUE EXPRESSION

Serotonin N-acetyltransferase (arylalkylamine N-acetyltransferase, AA- NAT, HGMW-approved symbol AANAT; EC 2,3,1.87) is the penultimate enzym e in melatonin synthesis and controls the night/day rhythm in melatoni n production in the vertebrate pineal gland. We have found that the hu man AA-NAT gene spans similar to 2.5 kb, contains four exons, and is l ocated at chromosome 17q25. The open reading frame encodes a 23.2-kDa protein that is similar to 80% identical to sheep and rat AA-NAT. The AA-NAT transcript (similar to 1 kb) is highly abundant in the pineal g land and is expressed at lower levels in the retina and hi the Y79 ret inoblastoma cell line. AA-NAT mRNA is also detectable at low levels in several brain regions and the pituitary gland, but not in several per ipheral tissues examined. Brain and pituitary AA-NAT could modulate se rotonin-dependent aspects of human behavior and pituitary function. (C ) 1996 Academic Press, Inc.