CHARACTERIZATION OF THE OVINE LH-BETA-SUBUNIT GENE - THE PROMOTER DIRECTS GONADOTROPE-SPECIFIC EXPRESSION IN TRANSGENIC MICE

The alpha- and beta-subunits of the gonadotropin hormones are expresse d in the gonadotrope cells of the anterior pituitary. There are no ade quate in vitro systems for the analysis of beta-subunit gene expressio n. In this study, therefore, transgenic mice have been used to investi gate the regulation of expression of the ovine luteinizing hormone bet a-gene (oLHbeta) in vivo. oLHbeta was isolated, characterized, and 1.9 kb of the promoter fused to the bacterial reporter chloramphenicol ac etyl-transferase (CAT). Three lines of transgenic mice were generated. CAT enzyme was detected in the pituitary of two lines, whereas the th ird line did not express. Measurement of endogenous luteinizing hormon e and follicle stimulating hormone levels in both expressing lines rev ealed small differences when compared to controls, but these did not a ffect the fertility of the animals. Immunostaining of the anterior pit uitary revealed that the oLHbetaCAT transgene was expressed specifical ly in gonadotrope cells.