Structural comparison of a portion of the rat and mouse growth hormone receptor/binding protein genes

A portion of the rat growth hormone receptor (GHR) gene was cloned by PCR. Restriction enzyme digestion and DNA sequence analyses revealed that an exon, exon 8A, encoding the carboxy terminus of the rat serum growth hormone binding protein (GHBP) was located between exons 7 and 8 of the rat GHR gene. Two tandem poly-adenylation (poly A) signals for the GHBP mRNA were found in the 3'-untranslated region of this exon. In addition, a GT repeat tract was found adjacent to the 5'-splice donor site of intron 7/8A. The similarity of the nucleotide sequences of the rat and mouse GHR/GP gene suggests that the poly A signals and GT repeat may be involved in the regulation of GHR and GHBP expression.