Properties of rat and mouse [beta]-glucuronidase mRNA and cDNA, including evidence for sequence polymorphism and genetic regulation of mRNA level

Abstract

cDNA clones containing partial sequences for [beta]-glucuronidase ([beta]G) were constructed from rat preputial gland RNA and identified by their ability to selectively hybridize [beta]G mRNA. One such rat clone was used to isolate several cross-hybridizing clones from a mouse-cDNA library prepared from kidney RNA from androgen-treated animals. Together, the set of mouse clones spans about 2.0 kb of the 2.6-kb [beta]G mRNA. Using these cDNA clones as probes, a genomic polymorphism for DNA restriction fragment size was found that proved to be genetically linked to the [beta]G gene complex. A fragment of [beta]G cDNA was subcloned into a vector carrying an SP6 polymerase promoter to provide a template for the in vitro synthesis of single-stranded RNA complementary to [beta]G mRNA. This provided an extremely sensitive probe for the assay of [beta]G mRNA sequences. Using either nick-translated cDNA or transcribed RNA as a hybridization probe, we found that mouse [beta]G RNA levels are strongly induced by testosterone, and that induction by testosterone is pituitarydependent. During the lag period preceding induction, during the induction period itself, and during deinduction following removal of testosterone, [beta]G mRNA levels paralleled rates of [beta]G synthesis previously measured by in vivo pulse-labelling experiments. Genetic variation in the extent of induction affected either the level of [beta]G mRNA or its efficiency of translation depending on the strain of mice tested.