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MPLKIP
M-phase-specific PLK1-interacting protein (TTD non-photosensitive 1 protein) is a protein that in humans is encoded by the MPLKIP gene (previously known as C7orf11). Patients with an inherited defect in both alleles of the gene suffer from trichothiodystrophy (TTD), a disease hallmarked by brittle hair and nails and usually by developmental difficulties as well. One patient carries a homozygous deletion of the whole gene area, which indicates that the gene is not essential for embryonic development. TTD can be diagnosed by the presence of tigertail-striped patterns in hair visible under polarised light microscopy, or biochemically by a reduced Cys content of the hairs. Only a minority of the TTD cases carry a MPLKIP defect: more frequently, the gene ERCC2 is mutated, which encodes a subunit of the protein complex TFIIH that is required for general transcription and for nucleotide excision repair Nucleotide excision repair is a DNA repair mechanism. DNA damage occurs constantly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichothiodystrophy
Trichothiodystrophy (TTD) is an autosomal recessive inherited disorder characterised by brittle hair and intellectual impairment. The word breaks down into ''tricho'' – "hair", '' thio'' – "sulphur", and ''dystrophy'' – "wasting away" or literally "bad nourishment". TTD is associated with a range of symptoms connected with organs of the ectoderm and neuroectoderm. TTD may be subclassified into four syndromes: Approximately half of all patients with trichothiodystrophy have photosensitivity, which divides the classification into syndromes with or without photosensitivity; BIDS and PBIDS, and IBIDS and PIBIDS. Modern covering usage is TTD-P (photosensitive), and TTD. Presentation Features of TTD can include photosensitivity, ichthyosis, brittle hair and nails, intellectual impairment, decreased fertility and short stature. A more subtle feature associated with this syndrome is a "tiger tail" banding pattern in hair shafts, seen in microscopy under polarized light. The acronyms ... [...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] |
Humans
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, and language. Humans are highly social and tend to live in complex social structures composed of many cooperating and competing groups, from families and kinship networks to political states. Social interactions between humans have established a wide variety of values, social norms, and rituals, which bolster human society. Its intelligence and its desire to understand and influence the environment and to explain and manipulate phenomena have motivated humanity's development of science, philosophy, mythology, religion, and other fields of study. Although some scientists equate the term ''humans'' with all members of the genus ''Homo'', in common usage, it generally refers to ''Homo sapiens'', the only extant member. Anatomically mod ... [...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] |
Homozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cysteine
Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, sometimes the symbol Cyz is used. The deprotonated form can generally be described by the symbol Cym as well. The thiol is susceptible to oxidation to give the disulfide derivative cystine, which serves an important structural role in many proteins. In this case, the symbol Cyx is sometimes used. When used as a food additive, it has the E number E920. Cysteine is encoded by the codons UGU and UGC. The sulfur-containing amino acids cysteine and methionine are more easily oxidized than the other amino acids. Structure Like other amino acids (not as a residue of a protein), cysteine exists as a zwitterion. Cysteine has chirality in the older / notation based on homology to - and -glyceraldehyde. In the newer ''R''/''S'' system of de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ERCC2
__NOTOC__ ERCC2, or XPD is a protein involved in transcription-coupled nucleotide excision repair. The XPD (ERCC2) gene encodes for a 2.3-kb mRNA containing 22 exons and 21 introns. The XPD protein contains 760 amino acids and is a polypeptide with a size of 87kDa. Defects in this gene can result in three different disorders: the cancer-prone syndrome xeroderma pigmentosum complementation group D, photosensitive trichothiodystrophy, and Cockayne syndrome. Just like XPB, XPD is a part of human transcriptional initiation factor TFIIH and has ATP-dependent helicase activity. It belongs to the RAD3/XPD subfamily of helicases. XPD is essential for the viability of cells. Deletion of XPD in mice is lethal for developing embryos. Consequences of mutations in ERCC2 The ERCC2/XPD protein participates in nucleotide excision repair and is used in unwinding the DNA double helix after damage is initially identified. Nucleotide excision repair is a multi-step pathway that removes a w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TFIIH
Transcription factor II Human (transcription factor II H; TFIIH) is an important protein complex, having roles in transcription of various protein-coding genes and DNA nucleotide excision repair (NER) pathways. TFIIH first came to light in 1989 when general transcription factor-δ or basic transcription factor 2 was characterized as an indispensable transcription factor in vitro. This factor was also isolated from yeast and finally named as TFIIH in 1992. TFIIH consists of ten subunits, 7 of which (ERCC2/XPD, ERCC3/XPB, GTF2H1/p62, GTF2H4/p52, GTF2H2/p44, GTF2H3/p34 and GTF2H5/TTDA) form the core complex. The cyclin activating kinase-subcomplex ( CDK7, MAT1, and cyclin H) is linked to the core via the XPD protein. Two of the subunits, ERCC2/XPD and ERCC3/ XPB, have helicase and ATPase activities and help create the transcription bubble. In a test tube these subunits are only required for transcription if the DNA template is not already denatured or if it is supercoiled. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
