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Endocrinology. 1996 Mar;137(3):846-56.

The Drosophila insulin receptor is required for normal growth.

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Department of Anatomy and Cell Biology, State University of New York, Brooklyn, New York 11203, USA.


Drosophila contain an insulin receptor homologue, encoded by the inr gene located at position 93E4-5 on the third chromosome. The receptor protein is strikingly homologous to the human receptor, exhibiting the same alpha2beta2 subunit structure and containing a ligand- activated tyrosine kinase in its cytoplasmic domain. Chemical mutagenesis was used to induce mutations in the inr gene and six independent mutations that lead to a loss of expression or function of the receptor protein were identified. These mutations are recessive, embryonic, or early larval lethals, but some alleles exhibit heteroallelic complementation to yield adults with a severe developmental delay (10 days), growth-deficiency, female-sterile phenotype. Interestingly, the severity of the mutant phenotype correlates with biochemical measures of loss of function of the receptor tyrosine kinase. The growth deficiency appears to be due to a reduction in cell number, suggesting a role for inr in regulation of cell proliferation during development. The phenotype is reminiscent of those seen in syndromes of insulin-resistance or IGF-I and IGF-I receptor deficiencies in higher organisms, suggesting a conserved function for this growth factor family in the regulation of growth and body size.

[Indexed for MEDLINE]

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