Systematic identification and integrative analysis of novel genes expressed specifically or predominantly in mouse epididymis.
BACKGROUND
Maturation of spermatozoa, including development of motility and the ability to fertilize the oocyte, occurs during transit through the microenvironment of the epididymis. Comprehensive understanding of sperm maturation requires identification and characterization of unique genes expressed in the epididymis.


RESULTS
We systematically identified 32 novel genes with epididymis-specific or -predominant expression in the mouse epididymis UniGene library, containing 1505 gene-oriented transcript clusters, by in silico and in vitro analyses. The Northern blot analysis revealed various characteristics of the genes at the transcript level, such as expression level, size and the presence of isoform. We found that expression of the half of the genes is regulated by androgens. Further expression analyses demonstrated that the novel genes are region-specific and developmentally regulated. Computational analysis showed that 15 of the genes lack human orthologues, suggesting their implication in male reproduction unique to the mouse. A number of the novel genes are putative epididymal protease inhibitors or beta-defensins. We also found that six of the genes have secretory activity, indicating that they may interact with sperm and have functional roles in sperm maturation.


CONCLUSIONS
We identified and characterized 32 novel epididymis-specific or -predominant genes by an integrative approach. Our study is unique in the aspect of systematic identification of novel epididymal genes and should be a firm basis for future investigation into molecular mechanisms underlying sperm maturation in the epididymis.
Oh
Jungsu
J
Department of Life Science, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea. tornado94@hanmail.net <tornado94@hanmail.net>
Lee
Jiae
J
Woo
Jong-Min
JM
Choi
Eunyoung
E
Park
Inju
I
Han
Cecil
C
Baek
Namhoe
N
Lee
Hoyong
H
Kim
Do Han
DH
Cho
Chunghee
C
D000818:Animals; D018076:DNA, Complementary / Q000235:genetics; D004822:Epididymis / Q000502:physiology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D015723:Gene Library; D008297:Male; D051379:Mice; D014176:Protein Biosynthesis; D014158:Transcription, Genetic
D018076:DNA, Complementary