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CABYR
Calcium-binding tyrosine phosphorylation-regulated protein is a protein that in humans is encoded by the ''CABYR'' gene. To reach fertilization competence, spermatozoa undergo a series of morphological and molecular maturational processes, termed capacitation, involving protein tyrosine phosphorylation and increased intracellular calcium. The protein encoded by this gene localizes to the principal piece of the sperm flagellum in association with the fibrous sheath and exhibits calcium-binding when phosphorylated during capacitation. A pseudogene on chromosome 3 has been identified for this gene. Transcript variants of this gene encode multiple protein isoforms A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene or gene family and are the result of genetic differences. While many perform the same or similar biological roles, some iso .... An additional transcript and isoform has not been fully characterized. R ... [...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 resid ... [...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 g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatozoa
A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell (biology), cell, or moving form of the ploidy, haploid cell (biology), cell that is the male gamete. A spermatozoon Fertilization, joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) Sperm cells contribute approximately half of the nuclear gene, genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing an X chromosome will lead to a female (XX) offspring, while one bearing a Y chromosome will lead to a male (XY) offspring. Sperm cells were first observed in Antonie van Leeuwenhoek's laboratory in 1677. Mammalian spermatozoon structure, function, and size Humans The human sperm cell is the Gamete, reproductive cell in males and will only survive in warm environments; once it leaves the male body th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capacitation
Capacitation is the penultimate step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte. This step is a biochemical event; the sperm move normally and look mature prior to capacitation. ''In vivo'', capacitation occurs after ejaculation, when the spermatozoa leave the vagina and enter the superior female reproductive tract. The uterus aids in the steps of capacitation by secreting sterol-binding albumin, lipoproteins, and proteolytic and glycosidasic enzymes such as heparin. For purposes of ''in vitro'' fertilization, capacitation occurs by incubating spermatozoa that have either undergone ejaculation or have been extracted from the epididymis and incubated in a defined medium for several hours. There are different techniques to perform the capacitation step: simple washing, migration (swim-up), density gradients, and filter. The objective is to isolate as many motile spermatozoa as possible and to eliminate non-motile or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrosine
-Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the Greek ''tyrós'', meaning ''cheese'', as it was first discovered in 1846 by German chemist Justus von Liebig in the protein casein from cheese. It is called tyrosyl when referred to as a functional group or side chain. While tyrosine is generally classified as a hydrophobic amino acid, it is more hydrophilic than phenylalanine. It is encoded by the codons UAC and UAU in messenger RNA. Functions Aside from being a proteinogenic amino acid, tyrosine has a special role by virtue of the phenol functionality. It occurs in proteins that are part of signal transduction processes and functions as a receiver of phosphate groups that are transferred by way of protein kinases. Phosphorylation of the hydroxyl group can change the activity of the targ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flagellum
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have from one to many flagella. A gram-negative bacterium ''Helicobacter pylori'' for example uses its multiple flagella to propel itself through the mucus lining to reach the stomach epithelium, where it may cause a gastric ulcer to develop. In some bacteria the flagellum can also function as a sensory organelle, being sensitive to wetness outside the cell. Across the three domains of Bacteria, Archaea, and Eukaryota the flagellum has a different structure, protein composition, and mechanism of propulsion but shares the same function of providing motility. The Latin word means "whip" to describe its lash-like swimming motion. The flagellum in archaea is called the archaellum to note its difference from the bacterial flagellum. Eukary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudogene
Pseudogenes are nonfunctional segments of DNA that resemble functional genes. Most arise as superfluous copies of functional genes, either directly by DNA duplication or indirectly by reverse transcription of an mRNA transcript. Pseudogenes are usually identified when genome sequence analysis finds gene-like sequences that lack regulatory sequences needed for transcription or translation, or whose coding sequences are obviously defective due to frameshifts or premature stop codons. Most non-bacterial genomes contain many pseudogenes, often as many as functional genes. This is not surprising, since various biological processes are expected to accidentally create pseudogenes, and there are no specialized mechanisms to remove them from genomes. Eventually pseudogenes may be deleted from their genomes by chance DNA replication or DNA repair errors, or they may accumulate so many mutational changes that they are no longer recognizable as former genes. Analysis of these degeneration ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome 3 (human)
Chromosome 3 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 3 spans almost 200 million base pairs (the building material of DNA) and represents about 6.5 percent of the total DNA in cells. Genes Number of genes The following are some of the gene count estimates of human chromosome 3. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome varies (for technical details, see gene prediction). Among various projects, the collaborative consensus coding sequence project ( CCDS) takes an extremely conservative strategy. So CCDS's gene number prediction represents a lower bound on the total number of human protein-coding genes. List of genes The following is a partial list of genes on human chromosome 3. For complete list, see the link in the infobox on the right. p-arm Partial list of the genes located on p-arm (short arm) of human chromosome 3 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcript Variants
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be included within or excluded from the final, processed messenger RNA (mRNA) produced from that gene. This means the exons are joined in different combinations, leading to different (alternative) mRNA strands. Consequently, the proteins translated from alternatively spliced mRNAs will contain differences in their amino acid sequence and, often, in their biological functions (see Figure). Biologically relevant alternative splicing occurs as a normal phenomenon in eukaryotes, where it increases the number of proteins that can be encoded by the genome. In humans, it is widely believed that ~95% of multi-exonic genes are alternatively spliced to produce functional alternative products from the same gene but many scientists believe that most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
