MOLECULAR-CLONING OF THE MOUSE ACTIVIN BETA(E) SUBUNIT GENE

cDNA clones encoding a novel activin beta subunit have been isolated f rom mouse liver cDNA library. An amino acid homology comparison among members of the TGF-beta superfamily indicates that the open reading fr ame codes for a new activin/inhibin beta subunit. The predicted mature region of the subunit shows >60% identity with activin beta(C) and be ta(D) and greater than or equal to 45% identity with activin beta(A) a nd beta(B), but only 20-40% amino acid sequence identity with other TG F-beta superfamily members. Therefore, the novel subunit has been desi gnated activin beta(E) Alignment of the mature growth factor region of the five activin beta subunits revealed that activin beta(A) and beta (B) share 63% amino acid identity, while activin beta(C), beta(D), and beta(E) share 62% identity. Therefore, activin beta(A) and beta(B) ar e most related to one another, while activin beta(C), beta(D), and bet a(E) may represent a subset of related sequences. (C) 1996 Academic Pr ess, Inc.