title: Expression of c-kit encoded at the W locus of mice in developing embryonic germ cells and presumptive melanoblasts.
abstract: The W locus of mice encodes the c-kit tyrosine kinase receptor. In embryos homozygous for severe W mutations, the number of germ cells does not increase after 8 days of development, melanocytes do not appear, and production of erythrocytes and mast cells is deficient. To gain some insight into the role of the c-kit receptor, we have used in situ hybridization to explore the time period of expression of c-kit transcripts in early germ cells and melanoblasts. At 6 1/2 days of development, expression was not seen in the embryonic cylinder, but did appear in parietal endoderm. Germ cells displayed a low level of c-kit transcripts from their first appearance in the 7 1/2 -day embryo, continuing through early proliferation and migration to the gonad. During migration, surrounding tissues also expressed c-kit. Expression increased in gonia and then ceased as they became nonproliferative. Expression in presumptive melanoblasts was first seen in the cervical region of 10-day embryos and continued as they spread over the surface of the body, entered the epidermis, and differentiated in hair follicles after birth. The effects of mutations of c-kit on germ cells and melanoblasts can be interpreted as an absence of a proliferative signal shortly after their segregation from other cell types. This signal may be required throughout the proliferative phase of early germ cells [and also in postnatal stages of germ cell development (Manova et al. (1990). Development 110, 1057-1069]. In melanoblasts, c-kit may play a role during both proliferation and differentiation.
authors.affiliation: Department of Cell Biology and Anatomy, Cornell University Medical College, New York 10021.
authors.forename: K
authors.initials: K
authors.lastname: Manova
authors.forename: R F
authors.initials: RF
authors.lastname: Bachvarova
mesh_terms: D000818:Animals; D005314:Embryonic and Fetal Development; D005260:Female; D015870:Gene Expression; D005854:Germ Cells / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008544:Melanocytes / Q000502:physiology; D051379:Mice; D008813:Mice, Inbred ICR; D009432:Neural Crest / Q000166:cytology* / Q000502:physiology; D009693:Nucleic Acid Hybridization; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases; D019009:Proto-Oncogene Proteins c-kit