C-kit gene is expressed by skin mast cells in embryos but not in puppies of Wsh/Wsh mice: age-dependent abolishment of c-kit gene expression.
The Wsh is a mutant allele at the W (c-kit) locus of mice, but no significant abnormalities are found at the coding region of the Wsh allele. Since cultured mast cells derived from the spleen of Wsh/Wsh mice do not express messenger RNA (mRNA) of c-kit, we studied the interrelation between the number of mast cells and the magnitude of c-kit mRNA expression in the skin of Wsh/Wsh mice of various ages. The number of mast cells in the skin of Wsh/Wsh embryos of 18 days postcoitum (pc) was approximately 40% that of normal control (+/+) embryos, but the number of mast cells decreased exponentially after birth; the number dropped to 0.6% that of +/+ mice at day 150 after birth. A weak but apparent signal of c-kit mRNA was detectable in the skin of 18-day pc Wsh/Wsh embryos by RNase protection assay but not in the skin of 5-day-old Wsh/Wsh mice. The number of c-kit protein-containing cells was significantly greater in the skin of 18-day pc Wsh/Wsh embryos than in the skin of 5-day-old Wsh/Wsh mice. The abolishment of c-kit mRNA expression appeared to be specific, because the expression of mast cell carboxypeptidase A mRNA but not of c-kit mRNA was detectable by in situ hybridization in skin mast cells of 5-day-old Wsh/Wsh mice. Taken together, the expression of c-kit mRNA was abolished first, then the content of c-kit protein dropped to undetectable levels, and then the disappearance of Wsh/Wsh mast cells themselves followed.
Yamazaki
M
M
Department of Pathology, Osaka University Medical School, Japan.
Tsujimura
T
T
Morii
E
E
Isozaki
K
K
Onoue
H
H
Nomura
S
S
Kitamura
Y
Y
D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D005260:Female; D005786:Gene Expression Regulation; D008407:Mast Cells / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009154:Mutation; D011247:Pregnancy; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000032:analysis; D020794:Receptor Protein-Tyrosine Kinases / Q000172:deficiency / Q000235:genetics*; D016184:Receptors, Colony-Stimulating Factor / Q000172:deficiency / Q000235:genetics*; D012867:Skin / Q000166:cytology / Q000196:embryology / Q000378:metabolism*
D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D016184:Receptors, Colony-Stimulating Factor; D019009:Proto-Oncogene Proteins c-kit; D020794:Receptor Protein-Tyrosine Kinases