Bodenin: a novel murine gene expressed in restricted areas of the brain

A gene trap screen designed to isolate novel mouse genes involved in nervous system development was performed. Here, we describe the isolation and characterization of a novel gene, bodenin, which is expressed in restricted areas of the brain. beta-Galactosidase marker gene activity was detected in the embryo at the start of organogenesis (embryonic day 8.5; E8.5). Staining gradually became stronger until E12.5, when embryos exhibited widespread expression. In brains of newborn and adult mice, beta-galactosidase staining was confined predominantly to forebrain structures. Transcriptional activity was also observed in kidney, liver, lung, heart, skeletal muscle, and testes. Part of the trapped gene was isolated by 5'-rapid amplification of cDNA ends (5'-RACE). Isolation and sequencing of the complete cDNA revealed an unknown gene encoding a 200 amino acid protein. Comparison with published sequences showed 94% amino acid identity to a human integrin cytoplasmic domain-associated protein. Mice homozygous for the mutation were viable and did not exhibit any obvious abnormal phenotype. However, concealed phenotypic abnormalities cannot be excluded. The lack of readily visible abnormalities may also be due to functional compensation or to the production of low levels of wild-type protein in mice homozygous for the gene trap vector insertion. Nevertheless, the restricted expression of bodenin in the brain of newborn and adult mice suggests a role for this novel gene in the developing and mature central nervous system.