Cloning and Sequence Analysis of a cDNA from Seminal Vesicle Tissue Encoding the Precursor of the Major Protein of Bull Semen

A cDNA library derived from poly(A)⁺RNA of bull seminal vesicle tissue was screened with a synthetic DNA probe specific for the major protein of bull semen. A positive clone pMP17, containing a 680-bp insert, was sequenced. In combination with primer-extension sequencing of poly(A)⁺RNA, a DNA sequence of 700 bp was determined. This DNA encodes a reading frame for 134 amino acids, starting with an ATG and terminated by a TAG codon. The first 25 amino acids constitute a signal peptide segment followed by 109 amino acids with the known sequence of the major protein. The initiation methionine occurs within the sequence CTACCATGG, which is highly homologous to a putative control signal for translational efficiency of mammalian mRNAs. The DNA sequence comprises a 3′ untranslated region of 276 bp and the polyadenylation signal AATAAA, 13 bp upstream from a tract of A residues. Northern analysis indicated the presence of a 750-bp mRNA species in poly(A)⁺RNA of seminal vesicle tissue. According to Southern analysis, one gene appears to specify the major protein of bull semen.