Isolation and nucleotide sequence analysis of a cloned cDNA encoding the beta-subunit of bovine follicle-stimulating hormone.

Two different cDNAs containing sequences coding for the beta-subunit of bovine follicle stimulating hormone (FSH-beta) have been isolated from a phage lambda gt11 bovine pituitary cDNA library. The complete nucleotide sequence of both clones was determined, and the combined sequence represents most of FSH-beta mRNA. The combined sequence contains 46 nucleotides of 5'-untranslated sequence followed by 387 nucleotides of coding sequence. The coding sequence predicts a 19-amino-acid amino-terminal precursor segment followed by the 110-amino-acid sequence of mature bovine FSH-beta. The cDNA sequence demonstrates the presence of a long 3'-untranslated region containing 1295 bases followed by a segment representing the poly(A) portion of the mRNA. Thus, the combined sequence of the cDNAs suggests a minimal size of 1.7 kb for FSH-beta mRNA. Analysis of FSH-beta sequences present in bovine pituitary mRNA demonstrated the presence of an mRNA with a size of about 2.0 kb. This apparent discrepancy is probably due to the presence of a several-hundred nucleotide tract of poly(A) at the 3' terminus of the mRNA. Comparison of the amino acid sequence predicted from the cDNA with the known amino acid sequence of the beta-subunit of FSH from several different species demonstrates that the protein has been highly conserved.