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Desensitization of IP 3 ‐induced Ca 2+ release by overexpression of a constitutively active Gqα protein converts ventral to dorsal fate in Xenopus early embryos
Author(s) -
Kume Shoen,
Saneyoshi Takeo,
Mikoshiba Katsuhiko
Publication year - 2000
Publication title -
development, growth and differentiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 66
eISSN - 1440-169X
pISSN - 0012-1592
DOI - 10.1046/j.1440-169x.2000.00519.x
Subject(s) - xenopus , microbiology and biotechnology , desensitization (medicine) , biology , signal transduction , receptor , stimulation , gq alpha subunit , g protein , endocrinology , medicine , biochemistry , gene
The constitutively active Gqα mutant construct (GqαQ‐L) in Xenopus early embryos was overexpressed and the effects on dorsoventral patterning examined. It was found that prolonged stimulation of inositol 1,4,5‐trisphosphate (IP 3 )‐Ca 2+ signaling by overexpression of GqαQ‐L led to desensitization of IP 3 ‐induced Ca 2+ release (IICR). Desensitization of IICR on the ventral side specifically induced an ectopic dorsal axis due to the conversion of ventral marginal mesoderm to adopt a dorsal fate. This effect of desensitization resembles that of inhibitory antibodies against the IP 3 receptor, as reported previously. These results strengthen the earlier finding that active IP 3 ‐Ca 2+ signaling functions in ventral signaling during the early embryonic development of Xenopus . Furthermore, the nature of downregulation of the Xenopus IP 3 receptor through continuous stimulation of IP 3 ‐Ca 2+ signaling might play a role in regulating endogenous IP 3 ‐Ca 2+ signaling in Xenopus early development.