Kap promoter analysis in vivo: a regulatory role for a truncated L1 repeat.

Reporter gene expression directed by a 1542-base pair (bp) fragment of the Kap promoter is specific to the proximal tubules of the kidney and androgen-regulated. In the present study, the characteristics of the androgen response from the 1542-bp promoter were examined in vivo. The estrogen response in the kidney and uterus was also examined. The reporter gene expression was assayed in lines of transgenic mice generated from a truncated promoter construct in which the L1 repeat, present at the distal portion of the 1542-bp, had been deleted. The pattern of androgen response of the reporter gene is similar to that of the endogenous Kap. Reporter gene expression in the 1542-bp promoter does not respond to estrogen in the kidney, while perinatal expression in the uterus does occur. Truncation of the L1 results in loss of reporter gene expression. We conclude that L1 sequences present near the Kap promoter have a regulatory function.