Genomic organization of the human myocilin gene (MYOC) responsible for primary open angle glaucoma (GLC1A)

Myocilin is a newly found cytoskeletal protein involved in the morphogenesis of the basal body, a major microtubule organizing center, of the ciliated epithelium. It was recently realized that myocilin is virtually identical to the independently reported protein TIGR (trabecular meshwork-induced glucocorticoid response), which is responsible for the pathogenesis of chromosome 1q-linked primary open angle glaucoma (GLC1A). In this paper, we determined the genomic organization of the myocilin (MYOC/TIGR) gene by analyzing the nucleotide sequence of the BAC clones containing the MYOC/TIGR gene. The MYOC/TIGR gene consists of three exons. Each of the two splice donor and acceptor sites agrees well with the GT/AG rule. Primer sets to amplify each of the three exons are designed. The 5'-flanking region of MYOC gene contains the TGTTCT sequence overlapped with a palindromic sequence TTCTTTTTAAAAAGAA, which appears to be a glucocorticoid responsive element. There is also a unique sequence of dinucleotide repeat [(GT)₂AA(GT)₄AC(GT)₁₃] which may also serve as a regulatory element. These results should aid in further detection of the MYOC/TIGR gene mutation and in depth understanding of the tissue-specific MYOC gene regulation.