Expression and characterization of an epididymis-specific gene.
A truncated cDNA coding a rabbit epididymal protein (BE-20) was identified in a previous study. In the present study the full-length cDNA was isolated by the method of rapid amplification of cDNA ends. The BE-20 cDNA consisted of 585 bp with a poly(A) tail of 26 residues and an open reading frame composed of 369 bp encoding a deduced polypeptide containing 123 amino acid residues with a calculated molecular mass of 13 kDa. The N-terminus-contained a leucine-rich segment. BE-20 cDNA has about 76.8% homology with the HE4 gene of human epididymis. Northern blot analysis of mRNAs prepared from 17 different human tissues was performed using as probe a 0.5-kb DNA fragment corresponding to a segment of BE-20 cDNA. Positive reaction was elicited only with epididymal mRNA. A DNA fragment corresponding to a section of the open reading frame of BE-20 cDNA was cloned in Escherichia coli under the control of the T7 promoter. The cellular content of the expressed recombinant protein comprised about 55% of the total protein. The chromatographically purified bacterial product migrated as a single band with an estimated M(r) of 15 kDa on analysis by SDS-PAGE. In conclusion, BE-20 cDNA is expressed only in the epididymis. It is structurally related to the four-disulfide core family of extracellular proteinase inhibitors and may be involved in sperm maturation.
Fan
H Y
HY
National Laboratory of Medical Molecular Biology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.
Miao
S Y
SY
Wang
L F
LF
Koide
S S
SS
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D004822:Epididymis; D015870:Gene Expression; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000235:genetics; D060589:Zyxin
D003598:Cytoskeletal Proteins; D018076:DNA, Complementary; D006023:Glycoproteins; D011993:Recombinant Fusion Proteins; C092842:ZYX protein, human; D060589:Zyxin