title: Mutation in the type IB bone morphogenetic protein receptor Alk6b impairs germ-cell differentiation and causes germ-cell tumors in zebrafish.
abstract: Germ-cell tumors (GCTs), which arise from pluripotent embryonic germ cells, exhibit a wide range of histologic differentiation states with varying clinical behaviors. Although testicular GCT is the most common cancer of young men, the genes controlling the development and differentiation of GCTs remain largely unknown. Through a forward genetic screen, we previously identified a zebrafish mutant line, tgct, which develops spontaneous GCTs consisting of undifferentiated germ cells [Neumann JC, et al. (2009) Zebrafish 6:319-327]. Using positional cloning we have identified an inactivating mutation in alk6b, a type IB bone morphogenetic protein (BMP) receptor, as the cause of the zebrafish GCT phenotype. Alk6b is expressed in spermatogonia and early oocytes, and alk6b mutant gonads display impaired BMP signal transduction, altered expression of BMP target genes, and abnormal germ-cell differentiation. We find a similar absence of BMP signaling in undifferentiated human GCTs, such as seminomas and embryonal carcinoma, but not in normal testis or in differentiated GCTs. These results indicate a germ-cell-autonomous role for BMP signal transduction in germ-cell differentiation, and highlight the importance of the BMP pathway in human GCTs.
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Joanie C
authors.initials: JC
authors.lastname: Neumann
authors.forename: Garvin L
authors.initials: GL
authors.lastname: Chandler
authors.forename: Vanessa A
authors.initials: VA
authors.lastname: Damoulis
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Fustino
authors.forename: Katherine
authors.initials: K
authors.lastname: Lillard
authors.forename: Leendert
authors.initials: L
authors.lastname: Looijenga
authors.forename: Linda
authors.initials: L
authors.lastname: Margraf
authors.forename: Dinesh
authors.initials: D
authors.lastname: Rakheja
authors.forename: James F
authors.initials: JF
authors.lastname: Amatruda
mesh_terms: D000483:Alleles; D000818:Animals; D001483:Base Sequence; D052005:Bone Morphogenetic Protein Receptors, Type I / Q000235:genetics* / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics*; D003001:Cloning, Molecular; D005260:Female; D056426:Genetic Loci / Q000235:genetics; D005854:Germ Cells / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008540:Meiosis; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D009373:Neoplasms, Germ Cell and Embryonal / Q000235:genetics* / Q000473:pathology*; D010053:Ovary / Q000378:metabolism / Q000473:pathology; D015398:Signal Transduction; D013094:Spermatozoa / Q000378:metabolism / Q000473:pathology; D013736:Testicular Neoplasms / Q000235:genetics / Q000473:pathology; D013737:Testis / Q000378:metabolism / Q000473:pathology; D015027:Zebrafish / Q000235:genetics*
chemical_list: D052005:Bone Morphogenetic Protein Receptors, Type I