According the EST sequence contained a UBA_NAD binding domain, a novel gene UBAL (ubiquitin-activating enzyme like protein) was cloning both in mouse and chicken by the homology scanning and EST splicing methods. UBAL contains the conserved domain Ⅰ of Uba1, ATP binding motif and putative active site Cys. The expression profile of mUBAL was detected in most of the tissues of the 11 investigated tissues, especially in kidney, testis, brain and heart. Whole-mount in situ hybridization with the coding region of mUBAL showed that expression of mUBAL was presented in the early streak stage of mouse embryo and migrated anterior with anterior visceral endoderm (AVE) and then in the telencephalon. The gUBAL expression was also found in the brain of HH14，HH 16 and HH18 chick embryos. The conserved structures and expression patterns of UBAL suggested that UBAL may play important roles in the developing brain of embryo and adult tissues as E1 like enzyme.