Analysis of the 5' region of the human tyrosine hydroxylase gene: combinatorial patterns of exon splicing generate multiple regulated tyrosine hydroxylase isoforms.

A single human gene has been described to encode multiple tyrosine hydroxylase (TH) mRNAs. The study of this variation has been extended by S1 mapping experiments and by analysis of the 5' region of the TH gene. Four different mRNAs were found to originate solely from alternative splicing of two exons. Comparison of the 5' flanking regions of human and rat genes discloses several highly conserved segments, likely to play an important role in the regulation of TH gene expression.