Consequences of exclusive expression in vivo of kit-ligand lacking the major proteolytic cleavage site Journal Article
| Authors: | Tajima, Y.; Moore, M. A. S.; Soares, V.; Ono, M.; Kissel, H.; Besmer, P. |
| Article Title: | Consequences of exclusive expression in vivo of kit-ligand lacking the major proteolytic cleavage site |
| Abstract: | Membrane growth factors that are processed to produce soluble ligands may function both as soluble factors and as membrane factors. The membrane growth factor Kit-ligand (KL), the ligand of the Kit receptor tyrosine kinase, is encoded at the Sl locus, and mice carrying Sl mutations have defects in hematopoiesis, gametogenesis, and melanogenesis. Two alternatively spliced KL transcripts encode two cell-associated KL protein products, KL-1 and KL-2. The KL-2 protein lacks the major proteolytic cleavage site for the generation of soluble KL, thus representing a more stable cell-associated form of KL. We investigated the consequences of exclusive expression of KL-2 in vivo. The KL gene in embryonic stem cells was modified and KL exon 6 was replaced with a PGKneoNTRtkpA cassette by homologous recombination, and mice carrying the Sl(KL2) allele were obtained. Sl/(KL2) mice had only slightly reduced levels of soluble KL in their serum, suggesting that in vivo KL-2 may be processed to produce soluble KL-2S. The steady-state characteristics of the hematopoietic system and progenitor numbers were normal, and the mutant animals were not anemic. However, mast cell numbers in the skin and peritoneum were reduced and the mutant animals displayed increased sensitivity to sublethal doses of γ-irradiation. Therefore, KL-2 may substitute for KL-1 in most situations with the exception of the production of mast cells, and induced proteolytic cleavage of KL-1 to produce soluble KL may have a role in the regeneration of hematopoietic tissue after radiation injury. |
| Keywords: | sequence deletion; nonhuman; radiation dose; animal cell; mouse; animals; mice; animal tissue; stem cell factor; gene expression; steady state; protein degradation; mice, mutant strains; embryo development; protein tyrosine kinase; radiation injury; mice, inbred c57bl; mice, transgenic; genetic recombination; protein processing, post-translational; membrane protein; alternative splicing; hematopoietic stem cells; gamma irradiation; hematopoiesis; binding sites; ligand binding; solubility; endopeptidases; radiation tolerance; mast cells; gamma rays; male; female; priority journal; article |
| Journal Title: | Proceedings of the National Academy of Sciences of the United States of America |
| Volume: | 95 |
| Issue: | 20 |
| ISSN: | 0027-8424 |
| Publisher: | National Academy of Sciences |
| Date Published: | 1998-09-29 |
| Start Page: | 11903 |
| End Page: | 11908 |
| Language: | English |
| DOI: | 10.1073/pnas.95.20.11903 |
| PUBMED: | 9751763 |
| PROVIDER: | scopus |
| PMCID: | PMC21738 |
| DOI/URL: | |
| Notes: | Article -- Export Date: 12 December 2016 -- Source: Scopus |
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