Complementary DNA cloning of the murine transforming growth factor-β3 (TGFβ3) precursor and the comparative expression of TGFβ3 and TGFβ1 messenger RNA in murine embryos and adult tissues

Murine transforming growth factor-β3 (TGFβ3) cDNAs were isolated from a TGFβ2-induced AKR-2B cDNA library. The composite cDNA sequence is 2894 nucleotides long, including 610-nucleotide and 1054-nucleotide 5′ and 3′ untranslated sequences, respectively. The murine TGFβ3-coding region is 1230 nucleotides in length and encodes a precursor protein of 410 amino acids, with a 96% peptide sequence identity with the human TGFβ3 precursor. Examination of TGFβ1 and TGFΒ3 mRNA levels in adult murine tissues showed that TGFβ1 mRNA expression is predominant in spleen, lung, and placenta. In contrast, TGFβ3 RNA was present in substantial amounts in brain, heart, adipose tissue, and testis. TGFβ3 mRNA is also observed in adult mouse lung and placenta. Both TGFβ1 and TGFβ3 RNAs were present in all stages of mouse fetal development studied from 10.5-17.5 days postcoitum, with higher levels observed in the latter stages. The differential expression of these TGFβ genes suggests that the various TGFβ species may have distinct physiological roles in vivo.