Characterization of mice deficient in the Src family nonreceptor tyrosine kinase Frk/rak.


Journal Article

Frk/rak belongs to a novel family of Src kinases with epithelial tissue-specific expression. Although developmental expression patterns and functional overexpression in vitro have associated these kinases with growth suppression and differentiation, their physiological functions remain largely unknown. We therefore generated mice carrying a null mutation in iyk, the mouse homolog of Frk/rak. We report here that frk/rak(-/-) mice are viable, show similar growth rates to wild-type animals, and are fertile. Furthermore, a 2-year study of health and survival did not identify differences in the incidence and spectrum of spontaneous tumors or provide evidence of hyperplasias in frk/rak(-/-) epithelial tissues. Histological analysis of organs failed to reveal any morphological changes in epithelial tissues that normally express high levels of Frk/rak. Ultrastructural analysis of intestinal enterocytes did not identify defects in brush border morphology or structural polarization, demonstrating that Frk/rak is dispensable for intestinal cytodifferentiation. Additionally, frk/rak-null mice do not display altered sensitivity to intestinal damage induced by ionizing radiation. cDNA microarray analysis revealed an increase in c-src expression and identified subtle changes in the expression of genes regulated by thyroid hormones. Significant decreases in the circulating levels of T3 but not T4 hormone are consistent with this observation and reminiscent of euthyroid sick syndrome, a stress-associated clinical condition.

Full Text

Cited Authors

  • Chandrasekharan, S; Qiu, TH; Alkharouf, N; Brantley, K; Mitchell, JB; Liu, ET

Published Date

  • July 2002

Published In

Volume / Issue

  • 22 / 14

Start / End Page

  • 5235 - 5247

PubMed ID

  • 12077350

Pubmed Central ID

  • 12077350

Electronic International Standard Serial Number (EISSN)

  • 1098-5549

International Standard Serial Number (ISSN)

  • 0270-7306

Digital Object Identifier (DOI)

  • 10.1128/mcb.22.14.5235-5247.2002


  • eng