Sequence analysis reveals that the BTG1 anti-proliferative gene is conserved throughout evolution in its coding and 3' non-coding regions.

The human BTG1 gene (expressing an anti-proliferative function) is an evolutionarily conserved gene homologous to the murine PC3/TIS21 genes. Here, we report the cloning and sequencing of the murine BTG1 coding region and chicken BTG1 cDNA. The putative human and mouse BTG1 proteins are 100% identical; the chicken BTG1 cDNA contains an open reading frame of 170 amino acids with a 91% identity to its human and murine counterparts. The 3'-untranslated region of BTG1 is also highly conserved (82% homology between human and chicken), suggesting that it plays a key role in the regulation of BTG1 expression. These data confirm that BTG1 is phylogenetically highly conserved and that BTG1 and PC3/TIS21 may constitute the first members of a new family of functionally related genes.