Region-specific variation of gene expression in the human epididymis as revealed by in situ hybridization with tissue-specific cDNAs.

Three tissue-specific gene probes that had been isolated by differential screening from a human epididymal cDNA library--HE1, HE2, and HE5--were employed to investigate regional specializations in the human epididymis. All 3 cDNAs were derived from major transcripts of the epithelial cells lining the epididymal duct. Each mRNA species, however, exhibited a discrete longitudinal pattern of hybridization with maxima in different regions of this organ, suggesting regional specializations of gene expression. The HE5 mRNA, which was recently shown to encode the peptide backbone of the human leukocyte differentiation antigen CDw52, showed maximum levels in the distal corpus epididymidis and in the vas deferens, whereas the HE2 mRNA was found predominantly in the caput and proximal corpus sections of the epididymis. HE1 mRNA was found in high amounts in all parts of the epididymis, displaying a 2-peak expression pattern with maxima in the distal caput and distal corpus of the epididymal duct.