engleski

ANALYSIS OF EXPRESSION AND FUNCTION OF STAM2 (SIGNAL TRANSDUCING ADAPTOR MOLECULE 1) IN THE OLFACTORY EPITHELIUM USING GENE TRAP MODIFIED MICE

STAM2 (Signal transducing adaptor molecule 2) was identified as a phosphotyrosine protein involved in cellular response to variety of cytokines and growth factors. Together with Hrs (hepatocyte growth factor regulated tyrosine kinase substrate) and Eps15 (EGFR pathway substrate clone no. 15) it has been implicated in endosome mediated intracellular membrane trafficking (1). In order to investigate expression and function of STAM2, mouse carrying a gene trap modification of Stam2 gene was created. Gene trap method involved genetical modification of embryonic stem (ES) cells with a nonhomologous DNA vector containing a splice acceptor and fused promotorless lacZ and neoR genes (2). After a large scale screen of obtained ES cells, corresponding mouse lines were produced, and the line carrying modification of Stam2 gene Stam2Gt1Gaj was selected for further investigation. As the expression of Stam2 indicated its possible function in the nervous system, general health and behavior Stam2Gt1Gaj homozygotes were compared to wild type C57Bl/6 mice. Homozygous mutant males had lower body mass, and both sexes preformed poorly in olfactory test. This indicated possible STAM2 function in regulation of body mass and sense of smell. Therefore the morphology of the olfactory region in homozygous mice and the expression of Stam2 were analyzed (3). Homozygous and wild type mice were fixed by perfusion (2% formaldehyde + 0.2% glutaraldehyde). Nasal mucose was isolated under a stereomicroscope, and beta-galactosidase activity was detected by histochemical staining with X-gal. The beta-galactosidase activity was visible in the olfactory part of the septal nasal mucosa, indicating Stam2 expression in the olfactory epithelium (Fig.1). Samples of septal nasal mucosa of homozygous and wild type mice were taken for electron microscopic analysis. Electron microscopic analysis did not reveal any difference in the ultrastructure of the olfactory sensory cells between homozigous and wild type mice (Fig. 2). Although Stam2 was confirmed to be expressed in the olfactory region of the nose, the morphology of the olfactory mucosa could not reveal Stam2 function in the olfaction.

Stam2; olfactory epithelium; mouse

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