title: Human melanoblasts in culture: expression of BRN2 and synergistic regulation by fibroblast growth factor-2, stem cell factor, and endothelin-3.
abstract: The BRN2 transcription factor (POU3F2, N-Oct-3) has been implicated in development of the melanocytic lineage and in melanoma. Using a low calcium medium supplemented with stem cell factor, fibroblast growth factor-2, endothelin-3 and cholera toxin, we have established and partially characterised human melanocyte precursor cells, which are unpigmented, contain immature melanosomes and lack L-dihydroxyphenylalanine reactivity. Melanoblast cultures expressed high levels of BRN2 compared to melanocytes, which decreased to a level similar to that of melanocytes when cultured in medium that contained phorbol ester but lacked endothelin-3, stem cell factor and fibroblast growth factor-2. This decrease in BRN2 accompanied a positive L-dihydroxyphenylalanine reaction and induction of melanosome maturation consistent with melanoblast differentiation seen during development. Culture of primary melanocytes in low calcium medium supplemented with stem cell factor, fibroblast growth factor-2 and endothelin-3 caused an increase in BRN2 protein levels with a concomitant change to a melanoblast-like morphology. Synergism between any two of these growth factors was required for BRN2 protein induction, whereas all three factors were required to alter melanocyte morphology and for maximal BRN2 protein expression. These finding implicate BRN2 as an early marker of melanoblasts that may contribute to the hierarchy of melanocytic gene control.
authors.affiliation: The Institute for Molecular Bioscience, Center for Functional and Applied Genomics, The University of Queensland, Brisbane, Australia.
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Cook
authors.forename: Philippe D
authors.initials: PD
authors.lastname: Donatien
authors.forename: Aaron G
authors.initials: AG
authors.lastname: Smith
authors.forename: Mark
authors.initials: M
authors.lastname: Murphy
authors.forename: Malcolm K
authors.initials: MK
authors.lastname: Jones
authors.forename: Meenhard
authors.initials: M
authors.lastname: Herlyn
authors.forename: Dorothy C
authors.initials: DC
authors.lastname: Bennett
authors.forename: J Helen
authors.initials: JH
authors.lastname: Leonard
authors.forename: Richard A
authors.initials: RA
authors.lastname: Sturm
mesh_terms: D000951:Antigens, Neoplasm; D002454:Cell Differentiation; D002478:Cells, Cultured; D019334:Endothelin-3 / Q000494:pharmacology*; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D018398:Homeodomain Proteins; D006801:Humans; D007150:Immunohistochemistry; D058965:MART-1 Antigen; D008544:Melanocytes / Q000737:chemistry / Q000166:cytology*; D014442:Monophenol Monooxygenase / Q000032:analysis; D009363:Neoplasm Proteins / Q000032:analysis; D009432:Neural Crest / Q000166:cytology*; D050809:POU Domain Factors; D019089:Stem Cell Factor / Q000494:pharmacology*; D013234:Stem Cells / Q000737:chemistry / Q000166:cytology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000032:analysis*
chemical_list: D000951:Antigens, Neoplasm; D019334:Endothelin-3; D018398:Homeodomain Proteins; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins; D050809:POU Domain Factors; D019089:Stem Cell Factor; D014157:Transcription Factors; C085076:transcription factor Brn-2; D016222:Fibroblast Growth Factor 2; D014442:Monophenol Monooxygenase; D013755:Tetradecanoylphorbol Acetate