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ZP3
Zona pellucida sperm-binding protein 3, also known as zona pellucida glycoprotein 3 (Zp-3) or the sperm receptor, is a ZP module-containing protein that in humans is encoded by the ''ZP3'' gene. ZP3 is the receptor in the zona pellucida which binds sperm at the beginning of fertilization. Function The zona pellucida (ZP) is a specialized extracellular matrix that surrounds the oocyte and early embryo. It is composed of three or four glycoproteins (ZP1-4) with various functions during oogenesis, fertilization and preimplantation development. The protein encoded by this gene is a major structural component of the ZP and functions in primary binding and stimulation of the sperm acrosome reaction. The nascent protein contains a N-terminal signal peptide sequence, a conserved "ZP domain" module, a consensus furin cleavage site (CFCS), a polymerization-blocking external hydrophobic patch (EHP), and a C-terminal transmembrane domain. Cleavage at the CFCS separates the mature protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zona Pellucida
The zona pellucida (plural zonae pellucidae, also egg coat or pellucid zone) is a specialized extracellular matrix that surrounds the plasma membrane of mammalian oocytes. It is a vital constitutive part of the oocyte. The zona pellucida first appears in unilaminar primary oocytes. It is secreted by both the oocyte and the ovarian follicles. The zona pellucida is surrounded by the corona radiata. The corona is composed of cells that care for the egg when it is emitted from the ovary. This structure binds spermatozoa, and is required to initiate the acrosome reaction. In the mouse (the best characterised mammalian system), the zona glycoprotein, ZP3, is responsible for sperm binding, adhering to proteins on the sperm plasma membrane. ZP3 is then involved in the induction of the acrosome reaction, whereby a spermatozoon releases the contents of the acrosomal vesicle. The exact characterisation of what occurs in other species has become more complicated as further zona proteins h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zona Pellucida-like Domain
The Zona pellucida-like domain (ZP domain / ZP-like domain / ZP module) is a large protein region of about 260 amino acids. It has been recognised in a variety of receptor-like eukaryotic glycoproteins. All of these molecules are mosaic proteins with a large extracellular region composed of various domains, often followed by either a transmembrane region and a very short cytoplasmic region or by a GPI-anchor. Functional and crystallographic studies revealed that the "ZP domain" region common to all these proteins is a protein polymerization module that consists of two distinct but structurally related immunoglobulin-like domains, ZP-N and ZP-C. The ZP module is located in the C-terminal portion of the extracellular region and – with the exception of non-polymeric family member ENG – contains 8 or 10 conserved Cys residues involved in disulfide bonds. The first 3D structure of a ZP module protein filament, native human uromodulin ( UMOD), was determined by cryo-EM. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilization
Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Processes such as insemination or pollination which happen before the fusion of gametes are also sometimes informally called fertilisation. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation. History In Antiquity, Aristotle conceived the formation of new individuals through fusion of male and female fluids, with form and function emerging gradually, in a mode called by him as epigenetic. In 1784, Spallanzani established the need of interaction between the female's ovum and male's sperm to form a zygote in fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sperm
Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, which are known as spermatozoa, while some red algae and fungi produce non-motile sperm cells, known as spermatia. Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm. Sperm cells form during the process known as spermatogenesis, which in amniotes (reptiles and mammals) takes place in the seminiferous tubules of the testes. This process involves the production of several successive sperm cell precursors, starting with spermatogonia, which differentiate into spermatocytes. The spermatocytes then undergo meiosis, reducing their chromosome number by half, which produces spermatids. The spermatids then mature and, in animals, construct a tail, or fla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Clawed Frog
The western clawed frog (''Xenopus tropicalis'') is a species of frog in the family Pipidae, also known as tropical clawed frog. It is the only species in the genus ''Xenopus'' to have a diploid genome. Its genome has been sequenced, making it a significant model organism for genetics that complements the related species ''Xenopus laevis'' (the African clawed frog), a widely used vertebrate model for developmental biology. ''X. tropicalis'' also has a number of advantages over ''X. laevis'' in research, such as a much shorter generation time (<5 months), smaller size ( body length), and a larger number of eggs per . It is found in , |
Sea Lamprey
The sea lamprey (''Petromyzon marinus'') is a parasitic lamprey native to the Northern Hemisphere. It is sometimes referred to as the "vampire fish". Description The sea lamprey has an eel-like body without paired fins. Its mouth is jawless, round and sucker-like, and as wide or wider than the head; sharp teeth are arranged in many concentric circular rows. There are seven branchial or gill-like openings behind the eye. Sea lampreys are olive or brown-yellow on the dorsal and lateral part of the body, with some black marblings, with lighter coloration on the belly. Adults can reach a length of up to and a body weight up to . Etymology The etymology of the genus name ''Petromyzon'' is from '' petro-'' "stone" and '' myzon'' "sucking"; ''marinus'' is Latin for "of the sea". Distribution and habitat The species is found in the northern and western Atlantic Ocean along the shores of Europe and North America, in the western Mediterranean Sea, the Black Sea, and as an invasive sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
