Cloning of the rat Gadd45 cDNA and its mRNA expression in the brain

We cloned the rat Gadd45 (growth arrest and DNA damage inducible) cDNA and examined its mRNA induction by y-ray irradiation in the rat brain. The rat Gadd45 cDNA sequence was highly homologous to the previously published human and hamster cDNAs, and was partially similar to the 28S rRNA gene. The mRNA encoding rat GADD45 was induced in the brain after γ-ray irradiation. This finding indicates that Gadd45 is an inducible gene following the ionizing radiation, not only in cultured cells in vitro, but also in animal tissues in vivo.