Microphthalmia (MITF) gene product, a transcription factor of the basic-helix-loop-helix type, is thought to play a role in the regulation of genes encoding the enzymes necessary for melanogenesis. These include tyrosinase, TRP-1 and TRP-2. Melanocyte-specific isoform of microphthalmia, MITF-M, is expressed in normal and malignant melanocytes. The presence of two other isoforms of microphthalmia, MITF-A and MITF-H, which differ from MITF-M in the amino-terminus, was demonstrated also in some non-melanocytic lineages. Here we have analyzed the presence of all three known isoforms of MITF mRNA in a panel of 17 human melanoma cell lines by a reverse transcriptase-polymerase chain reaction using isoform-specific primers. While, as expected, the predominant form in melanoma cell lines was MITF-M, low amounts of MITF-A mRNA was found in almost all melanomas, as well as in most of 20 tumor cell lines of the non-melanocyte origin (lung and colon carcinomas, osteosarcomas and neuroblastomas). The expression of MITF-H was not detected, with a few exceptions, in the tested cell lines. Pax3 transcription factor was reported earlier to regulate positively the melanocyte-specific promoter of the MITF gene. We found here that the Pax 3 mRNA was expressed in all melanoma cell lines, even in those that had repressed the MITF-M and were amelanotic. This suggests that additional factors, besides Pax3, are required for the MITF expression. The MSG1 (melanocyte-specific gene 1), a gene originally isolated from melanocytes and containing a strong transcription activation domain, was also found expressed in all melanomas and most non-melanocyte tumor cell lines. Together, these data indicate that the MITF-M isoform is the major type of MITF mRNA present in human melanoma cell lines and show that the expression of the isoform MITF-A and the MSG1 is not restricted to malignant melanocytes and occurs in a wide range of tumor cell lines.

• MeSH
• DNA vazebné proteiny biosyntéza   genetika   MeSH
• lidé MeSH
• melaniny biosyntéza   MeSH
• melanocyty metabolismus   MeSH
• melanom genetika   metabolismus   MeSH
• messenger RNA biosyntéza   MeSH
• nádorové buňky kultivované metabolismus   MeSH
• nádorové kmenové buňky metabolismus   MeSH
• nádorové proteiny biosyntéza   genetika   MeSH
• nádory metabolismus   patologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• protein - isoformy biosyntéza   genetika   MeSH
• regulace genové exprese u nádorů * MeSH
• RNA nádorová biosyntéza   MeSH
• slinné proteiny a peptidy biosyntéza   genetika   MeSH
• transkripční faktor PAX3 MeSH
• transkripční faktor spojený s mikroftalmií MeSH
• transkripční faktory paired box MeSH
• transkripční faktory * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• DNA vazebné proteiny MeSH
• melaniny MeSH
• messenger RNA MeSH
• MITF protein, human MeSH Prohlížeč
• nádorové proteiny MeSH
• PAX3 protein, human MeSH Prohlížeč
• Pax3 protein, mouse MeSH Prohlížeč
• protein - isoformy MeSH
• RNA nádorová MeSH
• slinné proteiny a peptidy MeSH
• Smr3a protein, mouse MeSH Prohlížeč
• transkripční faktor PAX3 MeSH
• transkripční faktor spojený s mikroftalmií MeSH
• transkripční faktory paired box MeSH
• transkripční faktory * MeSH