Vitellogenins(VITs)are the most abundant proteins in adult hermaphrodite Caenorhabditis elegans.VITs are synthesized in the intes-tine,secreted to the pseudocoelom,matured into yolk proteins,and finally deposited in o...Vitellogenins(VITs)are the most abundant proteins in adult hermaphrodite Caenorhabditis elegans.VITs are synthesized in the intes-tine,secreted to the pseudocoelom,matured into yolk proteins,and finally deposited in oocytes as nutrients for progeny development.How VITs are secreted out of the intestine remains unclear.Using immuno-electron microscopy(immuno-EM),we localize intestinal VITs along an exocytic pathway consisting of the rough endoplasmic reticulum(ER),the Golgi,and the lipid bilayer-bounded VIT vesicles(VVs).This suggests that the classic exocytotic pathway mediates the secretion of VITs from the intestine to the pseudocoe-lom.We also show that pseudocoelomic yolk patches(PYPs)are membrane-less and amorphous.The different VITs/yolk proteins are packed as a mixture into the above structures.The size of VVs can vary with the VIT levels and the age of the worm.On adult Day 2(AD 2),intestinal VVs(~200 nm in diameter)are smaller than gonadal yolk organelles(YOs,~500 nm in diameter).VVs,PYPs,and YOs share a uniform medium electron density by conventional EM.The morphological profiles documented in this study serve as a refer-ence for future studies of VITs/yolk proteins.展开更多
基金funded by the National Natural Science Foundation of China(NSFC-ISF 32061143020 to M.Q.D.,31925026 to F.S.,and 31501160 to X.X.L.)the Ministry of Science and Technology of the People's Republic of China(institutional grants to NIBS,Beijing,a fund of the National High-Level Talents Special Support Program to M.Q.D.)Beijing Municipal Science and Technology Commission(institutional grants to NIBS,Beijing and a fund for cultivation and development of innovation base to M.Q.D.).
文摘Vitellogenins(VITs)are the most abundant proteins in adult hermaphrodite Caenorhabditis elegans.VITs are synthesized in the intes-tine,secreted to the pseudocoelom,matured into yolk proteins,and finally deposited in oocytes as nutrients for progeny development.How VITs are secreted out of the intestine remains unclear.Using immuno-electron microscopy(immuno-EM),we localize intestinal VITs along an exocytic pathway consisting of the rough endoplasmic reticulum(ER),the Golgi,and the lipid bilayer-bounded VIT vesicles(VVs).This suggests that the classic exocytotic pathway mediates the secretion of VITs from the intestine to the pseudocoe-lom.We also show that pseudocoelomic yolk patches(PYPs)are membrane-less and amorphous.The different VITs/yolk proteins are packed as a mixture into the above structures.The size of VVs can vary with the VIT levels and the age of the worm.On adult Day 2(AD 2),intestinal VVs(~200 nm in diameter)are smaller than gonadal yolk organelles(YOs,~500 nm in diameter).VVs,PYPs,and YOs share a uniform medium electron density by conventional EM.The morphological profiles documented in this study serve as a refer-ence for future studies of VITs/yolk proteins.
