The bovine tyrosine hydroxylase gene associates in vitro with the nuclear matrix by its first intron sequence.

Recently we have shown that in vitro binding of the proximal part of the human tyrosine hydroxylase gene to the nuclear matrix is correlated with its transcriptional activity. The strongest binding potential was predicted by computing for the first intron sequence (Lenartowski & Goc, 2002, Neurosci Lett.; 330: 151-154). In this study a 16 kb fragment of the bovine genomic DNA containing the tyrosine hydroxylase gene was investigated for its affinity to the nuclear matrix. Only a 950 bp fragment encoding the distal part of the first intron, second exon and a few nucleotides of the second intron bound to the nuclear matrix. The binding was independent of the tissue-specific tyrosine hydroxylase gene activation. The fragment was subcloned and sequenced. Computer search pointed to one potential intronic matrix attachment region with two AP1-like sites embedded in the sequence. We conclude that even if the position of the matrix binding region is conserved among the tyrosine hydroxylase genes in mammals, its tissue specificity and/or function is not preserved or is achieved by different mechanisms.