Hen egg protein (HEP21) is a 21-kDa secreted protein and has a single copy of the Ly6/uPAR domain. Although HEP21 is expressed primarily in the chicken oviduct, its biological function(s) in the reproductive system of chickens is not known. Thus, in the present study, we investigated expression patterns of HEP21 with respect to hormonal regulation, oviduct development, changes in expression in laying hens undergoing induced molting, and in the development of ovarian carcinogenesis in laying hens. Results of present study indicated that HEP21 messenger RNA (mRNA) expression increased ( P < 0.001) in the chicken oviduct in response to estrogen. In situ hybridization analyses revealed expression of HEP21 mRNA predominantly in glandular (GE) and luminal epithelia of the magnum of the chicken oviduct in response to estrogen. The expression of HEP21 mRNA decreased ( P < 0.001) as the oviduct regressed during induced molting and increased ( P < 0.001) with recrudescence of the oviduct following molting. HEP21 mRNA was most abundant in GE of the oviduct during recrudescence, but not during oviduct regression following induced molting. Moreover, we found abundant expression of HEP21 in GE of cancerous ovaries, but not in normal ovaries of hens. Collectively, results of present study suggest that HEP21 is an estrogen-responsive gene in the oviduct of hens that likely regulates development of the chicken oviduct, and egg production and formation. Furthermore, there is increased expression of HEP21 in epithelial-derived ovarian cancer suggesting that HEP21 could be used for diagnosis and monitoring carcinogenesis in laying hens and in women.
Bibliographical noteFunding Information:
This research was funded by Basic Science Research Program ( 2013R1A1A2A10005948 ) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology , and also by a grant from the Next-Generation BioGreen 21 Program (No. PJ008142 ), Rural Development Administration, Republic of Korea. The authors thank members of the laboratory of Molecular Development Engineering for their constant support and appreciate Dr Fuller W. Bazer (Texas A&M University, USA) for their thoughtful editing and comments on our paper.
- Ovarian cancer
ASJC Scopus subject areas
- Food Animals
- Animal Science and Zoology