The human BAT3 ortholog in rodents is predominantly and developmentally expressed in testis.

A partial cDNA clone, RLC34, was isolated from a rat brain cDNA library. Its sequence exhibits high identity with BAT3 (88.4% and 94.9% for DNA and the deduced amino acid sequence, respectively), a gene located within the region of human major histocompatibility complex III (MCHIII region). RLC34 detected a transcript the same size in human and rat, similar to that reported for BAT3. Southern blot analysis of RLC34 showed similar restriction patterns as those of the human BAT3 gene. A panel of rodent tissue samples were examined and the RLC34 was found to be predominantly expressed in the germ cells of rodent testes. The expression is developmentally regulated with increased transcripts seen at 17-20 days after birth. Its testicular expression, its association with spermatogenesis, and its location in MCHIII suggest a correlation of RLC34 with the growth-reproduction complex (grc). This finding may also provide a clue to study the function of other genes localized in this area of the MCHIII region.