engleski

Functional analysis of mouse genes expressed in the central nervous system by gene trap approach

One approach to assess gene function in vivo is to create a mouse deficient for the gene of interest. In order to identify genes expressed during central nervous system development and in the same time to create a mutant mouse, the gene trap method was applied. Embryonic stem (ES) cells were genetically modified by a nonhomologous DNA vector containing a splice acceptor and fused promoterless genes lacZ and neoR. The vector was integrated randomly within the genome, and the inserted genes were active only if the vector was within a transcribed endogenous gene. As a result ES cells were resistant to neomycine (G418) selection. Moreover, expression of lacZ gene mirrored the expression of endogenous gene mutated by gene trap vector, hence its expression could be monitored in ES cells, but as well in ES-cell-derived mutant mice. The insertion was likely to disturb the endogenous gene and an insight in its function could be obtained by analyze of the phenotype of the mutated mice. Here we report the gene trap modification of two genes expressed in developing and adult brain. Signal transducing adaptor molecule 2 (Stam2) is expressed during development of the brain and the heart, and in the adult cortex and hippocampus. The phenotype analysis showed that the homozygous carriers of gene trap modification did not exhibit any obvious anomalies, they were fertile and several generations of homozygotes were obtained. Nevertheless as double knockout of Stam1 and Stam2 is embryonic lethal, Stams appear indispensable for embryo development. Nucleolar protein 1 (Nol1) is expressed in the nucleolus of proliferating cells, including those of the developing neural tube. Homozygote carriers of gene trap mutation of Nol1 gene die at the blastocyst stage. Although Nol1 expression is assigned to dividing cells, it is surprisingly expressed as well in the neurons of the adult brain, suggesting an additional unknown function in the nucleolus of neurons.

Stam2; Nol1; gene trap; CNS; mouse; embryo

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