A C-type lectin associated and translocated with cortical granules during oocyte maturation and egg fertilization in fish.
Oocyte maturation and egg fertilization in both vertebrates and invertebrates are marked by orchestrated cytoplasmic translocation of secretory vesicles known as cortical granules. It is thought that such redistribution of cellular content is critical for asymmetrical cell division during early development, but the mechanism and regulation of the process is poorly understood. Here we report the identification, purification and cDNA cloning of a C-type lectin from oocytes of a freshwater fish species gibel carp (Carassius auratus gibelio). The purified protein has been demonstrated to have lectin activity and to be a Ca(2+)-dependent C-type lectin by hemagglutination activity assay. Immunocytochemistry revealed that the lectin is associated with cortical granules, gradually translocated to the cell surface during oocyte maturation, and discharged to the egg envelope upon fertilization. Interestingly, the lectin becomes phosphorylated on threonine residues upon induction of exocytosis by fertilization and returns to its original state after morula stage of embryonic development, suggesting that this posttranslational modification may represent a critical molecular switch for early embryonic development.
Dong
Cai-Hua
CH
State Key Laboratory of Freshwater Ecology and Biotechnology, Wuhan Center for Developmental Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
Yang
Shu-Ting
ST
Yang
Zhong-An
ZA
Zhang
Lei
L
Gui
Jian-Fang
JF
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003594:Cytoplasmic Granules / Q000378:metabolism*; D019075:Electrophoresis, Capillary; D005306:Fertilization / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D006054:Goldfish; D037181:Lectins, C-Type / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism*; D010063:Ovum / Q000378:metabolism
D037181:Lectins, C-Type