IDENTIFICATION OF TISSUE-SPECIFIC DNASE I HYPERSENSITIVE SITES IN THE RABBIT FLAVIN-CONTAINING MONOOXYGENASE FORM 2 GENE

Previous studies demonstrated that the flavin-containing mo-nooxygenases (FMO) are expressed in a tissue-specific manner. To begin an elucidation of mechanisms regulating this expression pattern, genomic clones for rabbit FMO2 were isolated and char-acterized. Two clones were isolated from a AEMBL3 genomic Ii-brary and shown to span approximately 30 kilobase pairs but to contain only about 800 base pairs of coding information. Primer extension analysis was used to map the transcription start site, extending the previously published cDNA sequence by 17 base pairs. The FMO2 promoter does not utilize a classical TATA box, nor are HTF islands present (DNA domains rich in cleavable sites for 5-methyl-cytidine/guanosine-sensitive restriction enzymes). Rather, homology with promoters controlled by initiator elements is observed. Previous studies demonstrated FMO2 expression in rabbit pulmonary Clara and type II cells (Overby, Nishio, Lawton