A targeting mutation of tyrosine 1062 in Ret causes a marked decrease of enteric neurons and renal hypoplasia.
The Ret receptor tyrosine kinase plays a crucial role in the development of the enteric nervous system and the kidney. Tyrosine 1062 in Ret represents a binding site for the phosphotyrosine-binding domains of several adaptor and effector proteins that are important for the activation of intracellular signaling pathways, such as the RAS/ERK, phosphatidylinositol 3-kinase/AKT, and Jun-associated N-terminal kinase pathways. To investigate the importance of tyrosine 1062 for organogenesis in vivo, knock-in mice in which tyrosine 1062 in Ret was replaced with phenylalanine were generated. Although homozygous knock-in mice were born normally, they died by day 27 after birth and showed growth retardation. The development of the enteric nervous system was severely impaired in homozygous mutant mice, about 40% of which lacked enteric neurons in the whole intestinal tract, as observed in Ret-deficient mice. The rest of the mutant mice developed enteric neurons in the intestine to various extents, although the size and number of ganglion cells were significantly reduced. Unlike Ret-deficient mice, a small kidney developed in all knock-in mice, accompanying a slight histological change. The reduction of kidney size was due to a decrease of ureteric bud branching during embryogenesis. Thus, these findings demonstrated that the signal via tyrosine 1062 plays an important role in histogenesis of the enteric nervous system and nephrogenesis.
Jijiwa
Mayumi
M
Department of Pathology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
Fukuda
Toshifumi
T
Kawai
Kumi
K
Nakamura
Akari
A
Kurokawa
Kei
K
Murakumo
Yoshiki
Y
Ichihara
Masatoshi
M
Takahashi
Masahide
M
D000015:Abnormalities, Multiple / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000235:genetics; D017615:Enteric Nervous System / Q000002:abnormalities*; D007668:Kidney / Q000002:abnormalities*; D051379:Mice; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D016297:Mutagenesis, Site-Directed; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D051096:Proto-Oncogene Proteins c-ret; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D014443:Tyrosine / Q000235:genetics
D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D014443:Tyrosine; D004247:DNA; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C494999:Ret protein, mouse