title: Gene expression in the axolotl germ line: Axdazl, Axvh, Axoct-4, and Axkit.
abstract: Primordial germ cells (PGCs) in embryos of mammals and urodele amphibians are formed by induction in the absence of germ plasm. We describe expression of four germ cell-related genes through the germ cell cycle of the axolotl. The orthologs of vasa and daz-like are up-regulated in PGCs of tail bud embryos before the gonad forms and are expressed throughout the female germ cell cycle. Mammalian Oct-4 is a marker of pluripotency in embryonic cells. Axolotl Oct-4 has higher homology to Oct-4 than that found in other vertebrates. It is expressed in the equivalent of the mouse epiblast, in the posterior mesoderm of late gastrulae that gives rise to PGCs, and in diplotene growing oocytes, but not in presumptive PGCs after gastrulation. Finally, a c-kit homolog is expressed in gonadal oogonia and growing oocytes as in mice but is also not found in PGCs. The expression pattern in urodele gonadal germ cells is similar to that of other vertebrates, although the pattern in pregonadal PGCs is distinctly different from that of mice. We conclude that PGCs are restricted to the germ line later in urodeles than in mice or lack migration and proliferation programs.
authors.affiliation: Department of Cell Biology and Development, Weill Medical College of Cornell University, New York, New York, USA.
authors.forename: Rosemary F
authors.initials: RF
authors.lastname: Bachvarova
authors.forename: Thomas
authors.initials: T
authors.lastname: Masi
authors.forename: Matthew
authors.initials: M
authors.lastname: Drum
authors.forename: Nathan
authors.initials: N
authors.lastname: Parker
authors.forename: Ken
authors.initials: K
authors.lastname: Mason
authors.forename: Roger
authors.initials: R
authors.lastname: Patient
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Johnson
mesh_terms: D000557:Ambystoma / Q000196:embryology* / Q000502:physiology; D000818:Animals; D036703:Blastula / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics*; D004475:Ectoderm / Q000502:physiology; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000502:physiology; D005260:Female; D005775:Gastrula / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000502:physiology; D008648:Mesoderm / Q000502:physiology; D050814:Octamer Transcription Factor-3; D015513:Oncogene Proteins / Q000235:genetics*; D010053:Ovary / Q000196:embryology* / Q000502:physiology; D019009:Proto-Oncogene Proteins c-kit; D020365:RNA Helicases; D016601:RNA-Binding Proteins; D013623:Tail / Q000196:embryology / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics*
chemical_list: C101358:DAZL protein, human; D004268:DNA-Binding Proteins; D050814:Octamer Transcription Factor-3; D015513:Oncogene Proteins; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D019009:Proto-Oncogene Proteins c-kit; D020365:RNA Helicases