Expression of human oocyte-specific linker histone protein and its incorporation into sperm chromatin during fertilization
Received 20 August 2008; received in revised form 11 November 2008; accepted 24 November 2008. published online 14 January 2009.
Objective
To investigate the expression of oocyte-specific linker histone protein (hH1FOO) in human ovaries and its incorporation into sperm chromatin after intracytoplasmic sperm injection (ICSI).
Design
Laboratory study.
Setting
University hospital.
Patient(s)
Human ovarian tissues were obtained from patients at oophorectomy. Human oocytes and embryos were obtained from infertile patients undergoing IVF and ICSI.
Intervention(s)
A polyclonal rabbit antibody targeting the predicted hH1FOO protein was used for immunohistochemical analysis. Western blot analysis and the reverse transcriptase–nested polymerase chain reaction were done to detect hH1FOO in chromatin of germinal vesicle–stage oocytes through to two-cell embryos.
Main Outcome Measure(s)
The hH1FOO antibody reactivity of oocytes, ovarian tissues, and sperm chromatin after ICSI.
Result(s)
hH1FOO protein was localized in all oocytes from primordial to Graafian follicles. In unfertilized oocytes after ICSI, the chromatin of injected sperm was condensed without hH1FOO incorporation in 45.5% of oocytes, condensed with hH1FOO incorporation in 9%, and decondensed with hH1FOO incorporation in 45.5%. None of the oocytes contained decondensed sperm chromatin without hHFOO incorporation.
Conclusion(s)
hH1FOO protein was expressed by human oocytes from primordial follicles to early embryogenesis. Sperm nuclei that were still condensed after ICSI could be separated into two categories by hH1FOO incorporation, which might provide valuable information regarding failed fertilization.
cDepartment of Pathology, Keio University School of Medicine, Tokyo, Japan
dNational Institute of Crop Science, Tsukuba, Japan
eDepartment of Microbiology and Immunology, Keio University School of Medicine, Tokyo, Japan
Reprint requests: Naoaki Kuji, M.D., Department of Obstetrics and Gynecology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan (FAX: 81-3-3226-1667).
Y.M. has nothing to disclose. N.K. has nothing to disclose. Y.T. has nothing to disclose. M.T. has nothing to disclose. E.I. has nothing to disclose. S.K. has nothing to disclose. S.K. has nothing to disclose. Y.Y. has nothing to disclose.
Supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan (No. 17591757 and No. 19591910), and Grant-in-Aid from the National Research Institute for Child Health and Development (No. 18-1).
ABSTRACT