Project description:Despite central roles of egg coat proteins in gamete recognition, their functions and composition are poorly understood. Here, we report that the proteome of the egg coat in the solitary ascidian Ciona intestinalis, called vitelline coat (VC) fraction, contains more than 800 proteins identified by mass spectrometry-based analyses. Over 100 proteins were enriched in the VC fraction compared with the VC-free egg proteome. The most abundant component in the VC was an apolipoprotein-like protein. The VC contained multiple homologs of mammalian zona pellucida (ZP) proteins, the number of which was unexpectedly large and most of which possessed epidermal growth factor-like repeats. Furthermore, the present study revealed that two fibrinogen-like proteins, v-Themis-A and -B, both of which are expressed in the VC, are the molecules responsible for the two self-sterility loci that were identified by our previous genetic study in this species.
Project description:In angiosperms, female gamete differentiation, fertilization, and subsequent zygotic development occur in embryo sacs deeply embedded in the ovaries. Despite their importance in plant reproduction and development, how the egg cell is specialized, fuses with the sperm cell, and converts into an active zygote for early embryogenesis remains unclear. This lack of knowledge is partly attributable to the difficulty of direct analyses of gametes in angiosperms. In this study, proteins from egg and sperm cells obtained from Oryza sativa flowers were separated by one-dimensional polyacrylamide gel electrophoresis and globally identified by highly sensitive liquid chromatography coupled with tandem mass spectroscopy. Proteome analyses were also conducted for seedlings, callus, and pollen grains to compare their protein expression profiles to those of gametes. Database was searched using Mascot software (ver.2.2.1, Matrix Science, MA, USA) with the following parameters. The fixed modification was propionasmide (Cys) and variable modification parameters were pyro-Glu, acetylation (protein N-terminus), and oxidation (Met). The maximum missed cleavage was set at 3 with a peptide mass tolerance of +/– 15 ppm. Peptide charges from +2 to +4 states and MS/MS tolerances of +/– 0.8 Da were allowed.
Project description:Vertebrate oocytes are coated with a special extracellular matrix termed egg-coat or Zona pellucida (ZP). Egg-coat is constituted by several ZP glycoproteins. In chicken fertilization, ejaculated sperm releases enzyme(s) to solubilize the ZP glycoprotein(s) for penetrating the egg-coat. In this study, we analyzed the solubilized ZP glycoprotein fragment. We also analyzed the glycosylation property of its fragment.