Sequence homology between tyrosine hydroxylase mRNA and a rat adrenal medullary cDNA

A rat adrenal medullary recombinant clone has been isolated by cross-hybridization with a tyrosine hydroxylase (TH) cDNA. The new clone has a mRNA size of 5.6 kb and also hybridizes to the 1.9-kb tyrosine hydroxylase message. Southern blot analysis reveals several hybridizing bands in common between the TH cDNA and the adrenal medullary clone. These results demonstrate that the adrenal clone shares sequences in common with the TH gene and/or is closely linked to it in the genome. Hybrid-selected mRNA translation products of the adrenal clone can be immunoprecipitated with dopamine beta hydroxylase antisera. This suggests that the adrenal medullary cDNA may code for another catecholamine pathway enzyme.