Structural organization of the human tyrosinase gene and sequence analysis and characterization of its promoter region.

Tyrosinase is the principal enzyme in the biosynthesis of melanin. The expression of tyrosinase is tissue-specific and appears to be regulated by various hormonal and environmental factors. Elucidation of the genomic structure and molecular basis of control of tyrosinase gene expression will greatly enhance our understanding of the regulation of human pigmentation. To this end, we have isolated and performed restriction mapping of recombinant cosmid and lambda phage clones containing the human tyrosinase gene, sequenced a 2.2-kilobase (kb) region of its promoter, and determined the potential regions regulating the tyrosinase gene expression in transient-expression system. The human tyrosinase gene is comprised of five exons and four introns. Based on our restriction mapping studies, the gene spans a distance of over 65-kb on chromosome 11 (q14-->q21). We constructed a series of plasmids (pHTY-CAT) that contain 5' sequential deletions of the human tyrosinase 5' flanking sequence fused to the reporter gene, chloramphenicol acetyltransferase (CAT). The plasmids were used to locate promoter regions that are potential regulators of tyrosinase gene expression in a transient expression system using melanoma cell lines. In human melanoma cells, the plasmid construct with a -2020 base pair (bp) promoter yielded the highest CAT activity. When the deletions reached -1739 bp, the CAT activity was dramatically reduced, indicating that important enhancer elements for transcription control are present between -1739 and -2020 bp. Further deletions up to -550 bp also resulted in dramatic decreases of CAT activity. However, when the deletion included -550 bp of the 5' flanking sequence, there was 26 percent of the CAT activity compared to that of the -2020 bp promoter. Deletions beyond -550 bp also showed markedly decreased CAT activity. Based on our data, we suggest that human tyrosinase gene expression is governed by both tissue-specific and multiple regulatory elements.

[1]  J. Sambrook,et al.  Molecular Cloning: A Laboratory Manual , 2001 .

[2]  S. Shibahara,et al.  Identification of a cis-acting element that enhances the pigment cell-specific expression of the human tyrosinase gene. , 1992, The Journal of biological chemistry.

[3]  B. Kwon,et al.  A single base insertion in the putative transmembrane domain of the tyrosinase gene as a cause for tyrosinase-negative oculocutaneous albinism. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[4]  M. Klüppel,et al.  The mouse tyrosinase promoter is sufficient for expression in melanocytes and in the pigmented epithelium of the retina. , 1991, Proceedings of the National Academy of Sciences of the United States of America.

[5]  R. Spritz,et al.  Organization and nucleotide sequences of the human tyrosinase gene and a truncated tyrosinase-related segment. , 1991, Genomics.

[6]  U. Francke,et al.  Homozygous tyrosinase gene mutation in an American black with tyrosinase-negative (type IA) oculocutaneous albinism. , 1991, American journal of human genetics.

[7]  F. Bosch,et al.  Rescue of the albino phenotype by introduction of a functional tyrosinase gene into mice. , 1990, The EMBO journal.

[8]  I. Weinstein,et al.  Identification of ultraviolet-inducible proteins that bind to a TGACAACA sequence in the polyoma virus regulatory region. , 1990, Cancer research.

[9]  R. Spritz,et al.  Detection of mutations in the tyrosinase gene in a patient with type IA oculocutaneous albinism. , 1990, The New England journal of medicine.

[10]  H. Yamamoto,et al.  Characteristic sequences in the upstream region of the human tyrosinase gene. , 1989, Biochimica et biophysica acta.

[11]  A. Takeda,et al.  Human oculocutaneous albinism caused by single base insertion in the tyrosinase gene. , 1989, Biochemical and biophysical research communications.

[12]  D. Barton,et al.  Isolation, chromosomal mapping, and expression of the mouse tyrosinase gene. , 1989, The Journal of investigative dermatology.

[13]  S. Shibahara,et al.  Functional analysis of the cDNA encoding human tyrosinase precursor. , 1989, Biochemical and biophysical research communications.

[14]  A. Houghton,et al.  Induction of pigmentation in mouse fibroblasts by expression of human tyrosinase cDNA , 1989, The Journal of experimental medicine.

[15]  H. Yamamoto,et al.  Melanin production in cultured albino melanocytes transfected with mouse tyrosinase cDNA. , 1989, Idengaku zasshi.

[16]  V. Hearing,et al.  Analysis of mammalian pigmentation at the molecular level. , 1989, Pigment cell research.

[17]  M. Beato.  Gene regulation by steroid hormones , 1989, Cell.

[18]  S. Shibahara,et al.  Molecular basis for the heterogeneity of human tyrosinase. , 1988, The Tohoku journal of experimental medicine.

[19]  W. Herr,et al.  The ubiquitous octamer-binding protein Oct-1 contains a POU domain with a homeo box subdomain. , 1988, Genes & development.

[20]  G. Schütz,et al.  Functional analysis of alternatively spliced tyrosinase gene transcripts. , 1988, The EMBO journal.

[21]  G. Schütz,et al.  Multiple transcripts of the mouse tyrosinase gene are generated by alternative splicing. , 1988, The EMBO journal.

[22]  D. Barton,et al.  Human tyrosinase gene, mapped to chromosome 11 (q14----q21), defines second region of homology with mouse chromosome 7. , 1988, Genomics.

[23]  B. Kwon,et al.  Sequence analysis of mouse tyrosinase cDNA and the effect of melanotropin on its gene expression. , 1988, Biochemical and biophysical research communications.

[24]  B. Kwon,et al.  Isolation and sequence of a cDNA clone for human tyrosinase that maps at the mouse c-albino locus. , 1987, Proceedings of the National Academy of Sciences of the United States of America.

[25]  M. Karin,et al.  Transcription factor AP-2 mediates induction by two different signal-transduction pathways: Protein kinase C and cAMP , 1987, Cell.

[26]  R. Tjian,et al.  Activation of transcription by two factors that bind promoter and enhancer sequences of the human metallothionein gene and SV40 , 1987, Nature.

[27]  P Bucher,et al.  Compilation and analysis of eukaryotic POL II promoter sequences. , 1986, Nucleic acids research.

[28]  B Sollner-Webb,et al.  High level transient expression of a chloramphenicol acetyl transferase gene by DEAE-dextran mediated DNA transfection coupled with a dimethyl sulfoxide or glycerol shock treatment. , 1984, Nucleic acids research.

[29]  E. Neumann,et al.  Gene transfer into mouse lyoma cells by electroporation in high electric fields. , 1982, The EMBO journal.

[30]  B. Kwon,et al.  Conserved cysteine to serine mutation in tyrosinase is responsible for the classical albino mutation in laboratory mice. , 1990, Nucleic acids research.

[31]  H. S. Mason.  The chemistry of melanin; mechanism of the oxidation of dihydroxyphenylalanine by tyrosinase. , 1948, The Journal of biological chemistry.