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Novel human, mouse and xenopus genes encoding a member of the RAS superfamily of low‐molecular‐weight GTP‐binding proteins and its downregulation in W/W V mouse jejunum
Author(s) -
DAIGO YATARO,
TAKAYAMA ICHIRO,
PONDER BRUCE AJ,
CALDAS CARLOS,
WARD SEAN M,
SANDERS KENTON M,
FUJINO MASAYUKI A
Publication year - 2004
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1111/j.1440-1746.2004.03298.x
Subject(s) - microbiology and biotechnology , biology , interstitial cell of cajal , gene expression , gene , gtpase , complementary dna , ras superfamily , gtp' , biochemistry , endocrinology , smooth muscle , enzyme
Background and Aim: Interstitial cells of Cajal (ICC) are pacemakers and mediators of neurotransmission in gastroenteric smooth muscles. Interstitial cells of Cajal require cellular signaling via KIT, a receptor tyrosine kinase, for development and maintenance of cellular phenotype. Much of the evidence demonstrating the functions of ICC comes from studies of W/W V mutant mice, which have reduced KIT function. The aim of the present study was to differentially examine gene expression in the small intestines of wild‐type and W/W V mice. Methods: RNA from the jejunum of wild‐type and W/W V mice was analyzed using a differential gene display method. Results: One candidate gene, encoding a novel small GTPase of the RAS superfamily, was significantly suppressed both in fed and starved W/W V mice. The full‐length clone of the murine gene and its human and xenopus counterparts were designated GTP‐binding protein, 28 kDa ( G28K ). Human G28K cDNA encodes a protein of 258 amino acids with homology to the human cell division cycle 42/ G25K protein. This gene is located at 1q42.11–q42.3. G28K was abundantly expressed in the human stomach and the small intestine. Semi‐quantitative reverse transcription–polymerase chain reaction analysis revealed expression of G28K mRNA within single isolated ICC. Conclusions: Gene analysis showed that G28K was differentially expressed in the small intestines of wild‐type and W/W V mice. Interstitial cells of Cajal within the small intestine expressed mRNA for G28K . The specific downregulation of G28K in the jejunum of W/W V mice, and high expression in human intestinal tissue suggest that the G28K gene might be associated with ICC function in mice and in humans.