BOVINE ACTIVIN RECEPTOR-TYPE-II CDNA - CLONING AND TISSUE EXPRESSION

The cDNA encoding the bovine activin type LT receptor has been cloned by reverse transcription-polymerase chain reaction (RT-PCR) amplificat ion of a bovine testicular RNA preparation. Sequence comparisons of th e bovine activin type II receptor with its human, mouse and rat homolo gues show strong evolutionary conservation at the nucleotide level of 94.9%, 93.5%, 92.9% and at the amino acid level of 98.6%, 99.0%, 98.8% , respectively. Bovine activin type II receptor mRNA is widely but not strongly expressed in reproductive tissues, with a major RNA band at 6 kb and minor bands at 5 kb and 3 kb. The differential levels of expr ession observed in these tissues suggest that levels of bActRII gene e xpression are regulated. Furthermore, we have observed decreasing leve ls of the bovine activin type II receptor mRNA with testes maturation.