ULTRASTRUCTURAL LOCALIZATION OF M1 FUSION PROTEIN ON EQUATORIAL SEGMENT OF ACROSOME INTACT AND FREE/REACTED HAMSTER SPERMATOZOA

Abstract

This study was designed to investigate the precise localization of M1 antigen and its expression factor(s) on hamster sperm which subjected to physiological and non-physiological conditions for acrosome reaction by correlating light and electron microscope observation. Acrosome-intact and acrosome-free or reacted hamster sperm were prepared. In sperm preparation, the same samples of each preparation were subjected in parallel to indirect immunofluorescent staining (IIF) and indirect immunogold labeling (IIG). Acrosome-free or reacted sperm were prepared by mechanical (sonication), physiological (incubation in medium which can induced spontaneous acrosome reaction) and chemical (incubation in calcium ionophore) procedure, respectively. Acrosome-intact sperm remained untreated. Results showed the M1 antigen that involved in sperm-oocyte fusion is localized in the equatorial segment region of hamster sperm, and the expression is Ca²⁺ and acrosome reaction dependent.

Kajian telah dijalankan untuk menentukan kedudukan antigen M1 serta faktor yang mempengaruhi pengekspresan terhadap sperma hamster yang telah mengalami tindak balas akrosom secara fisiologi dan bukan fisiologi dengan mengaitkan keputusan pemerhatian melalui mikroskop cahaya dan elektron. Kaedah kajian melibatkan penyediaan sperma hamster dengan akrosom dan tanpa akrosom atau telah mengalami tindak balas akrosom. Dalam penyediaan sampel sperma, setiap sampel perlakuan menjalani kaedah pewarnaan imunopendarfluor dan pelabelan imunoemas secara selari. Sperma tanpa akrosom atau telah mengalami tindak balas akrosom masing-masing disediakan melalui prosedur mekanik (sonikasi), fisiologi (eraman dalam medium yang sesuai untuk tindak balas akrosom spontan) dan kimia (eraman dalam kalsium ionofor); manakala sperma dengan akrosom tidak diperlaku sebarang prosedur. Keputusan kajian menunjukkan antigen M1 yang merupakan molekul protein yang terlibat dalam pelakuran sperma-oosit berada di bahagian dalam segmen khatulistiwa, dan pengekspresannya bergantung pada kehadiran Ca²⁺ dan tindak balas akrosom.