Regulation of hematopoietic development in the aorta-gonad-mesonephros region mediated by Lnk adaptor protein.
Development of hematopoietic cells in the aorta-gonad-mesonephros (AGM) region in the midgestation mouse embryo involves a multistep process, sequentially changing from endothelial cell-like cells, including hemangioblasts, into hematopoietic stem cells, progenitors, and/or lineage-committed cells. An adaptor molecule, Lnk, is known to negatively control the production of pro- and pre-B cells and hematopoietic progenitor cells in adult bone marrow. Here we show a role of Lnk in hematopoietic development in the AGM region. Lnk was predominantly expressed in the endothelial cells lining the dorsal aorta at embryonic day 11.5 (E11.5). Overexpression of Lnk in the primary culture of the AGM region at E11.5 suppressed the emergence of CD45+ hematopoietic cells. Point mutation in the SH2 domain of Lnk, which abolishes the binding capability of Lnk to c-Kit upon stimulation with stem cell factor (SCF), led to loss of Lnk-dependent inhibition of hematopoietic cell development in AGM cultures, suggesting Lnk-mediated inhibition of the SCF/c-Kit signaling pathway. In cultured AGM cells from Lnk homozygous mutant mouse embryos, the number of emerged CD45+ cells was 2.5-fold larger than that from heterozygous littermates. Furthermore, aorta cells of E11.5 Lnk homozygous mutant mice also showed enhanced hematopoietic colony-forming activity. Thus, Lnk is a negative regulator of hematopoiesis in the AGM region.
Nobuhisa
Ikuo
I
Department of Cell Fate Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan.
Takizawa
Makiko
M
Takaki
Satoshi
S
Inoue
Hirofumi
H
Okita
Keisuke
K
Ueno
Masaya
M
Takatsu
Kiyoshi
K
Taga
Tetsuya
T
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001011:Aorta / Q000196:embryology; D001483:Base Sequence; D046508:Culture Techniques; D004247:DNA / Q000235:genetics; D016222:Fibroblast Growth Factor 2 / Q000502:physiology; D015870:Gene Expression; D006066:Gonads / Q000196:embryology; D006410:Hematopoiesis / Q000502:physiology*; D006579:Heterozygote; D006720:Homozygote; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008650:Mesonephros / Q000196:embryology; D051379:Mice; D008813:Mice, Inbred ICR; D018345:Mice, Knockout; D017354:Point Mutation; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D019089:Stem Cell Factor / Q000502:physiology; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D047908:Intracellular Signaling Peptides and Proteins; C490777:Lnk protein, mouse; D008565:Membrane Proteins; D011506:Proteins; D019089:Stem Cell Factor; D016222:Fibroblast Growth Factor 2; D004247:DNA