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Chromosome Scaffold
In biology, the chromosome scaffold is the backbone that supports the structure of the chromosomes. It is composed of a group of Non-histone protein, non-histone proteins that are essential in the structure and maintenance of eukaryotic chromosomes throughout the cell cycle. These scaffold proteins are responsible for the DNA_condensation, condensation of chromatin during mitosis. Origin In the late 1970s, Ulrich K. Laemmli and colleagues discovered a backbone structure in eukaryotic chromosomes after they depleted the histone proteins. This backbone was localized along the chromosome axis, and was termed the ‘chromosome scaffold’. Proteins of the scaffold In eukaryotic organisms, the DNA of each cell (biology), cell is organized into separated chromosomes, which are composed of chromatin, a mixture of DNA and many different groups of proteins. Among them, the structural proteins (that are not histones) bind the chromatin fiber around themselves forming a long, continuous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biology
Biology is the scientific study of life and living organisms. It is a broad natural science that encompasses a wide range of fields and unifying principles that explain the structure, function, growth, History of life, origin, evolution, and distribution of life. Central to biology are five fundamental themes: the cell (biology), cell as the basic unit of life, genes and heredity as the basis of inheritance, evolution as the driver of biological diversity, energy transformation for sustaining life processes, and the maintenance of internal stability (homeostasis). Biology examines life across multiple biological organisation, levels of organization, from molecules and cells to organisms, populations, and ecosystems. Subdisciplines include molecular biology, physiology, ecology, evolutionary biology, developmental biology, and systematics, among others. Each of these fields applies a range of methods to investigate biological phenomena, including scientific method, observation, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural 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 residues i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NCAPG
Condensin complex subunit 3 also known as condensin subunit CAP-G (CAP-G) or non-SMC condensin I complex subunit G (NCAPG) is a protein that in humans is encoded by the ''NCAPG'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. 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: protei .... CAP-G is a subunit of condensin I, a large protein complex involved in chromosome condensation. Interactions NCAPG has been shown to interact with DNMT3B. References Further reading * * * * * Human proteins {{gene-4-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinesin
A kinesin is a protein complex belonging to a class of motor proteins found in eukaryotic cells. Kinesins move along microtubule (MT) filaments and are powered by the hydrolysis of adenosine triphosphate (ATP) (thus kinesins are ATPases, a type of enzyme). The active movement of kinesins supports several cellular functions including mitosis, meiosis and transport of cellular cargo, such as in axonal transport, and intraflagellar transport. Most kinesins walk towards the plus end of a microtubule, which, in most cells, entails transporting cargo such as protein and membrane components from the center of the cell towards the periphery. This form of transport is known as anterograde transport. In contrast, dyneins are motor proteins that move toward the minus end of a microtubule in retrograde transport. Discovery The first kinesins to be discovered were microtubule-based anterograde intracellular transport motors in 1985, based on their motility in cytoplasm extruded from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topologically Associating Domain
A topologically associating domain (TAD) is a self-interacting genomic region, meaning that DNA sequences within a TAD physically interact with each other more frequently than with sequences outside the TAD. The average size of a topologically associating domain (TAD) is 1000 kb in humans, 880 kb in mouse cells, and 140 kb in fruit flies. Boundaries at both side of these domains are conserved between different mammalian cell types and even across species and are highly enriched with CTCF, CCCTC-binding factor (CTCF) and cohesin. In addition, some types of genes (such as transfer RNA genes and housekeeping genes) appear near TAD boundaries more often than would be expected by chance. The functions of TADs are not fully understood and are still a matter of debate. Most of the studies indicate TADs regulate gene expression by limiting the Enhancer (genetics), enhancer-Promoter (genetics), promoter interaction to each TAD; however, a recent study uncouples TAD organization and gene exp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMC4
Structural maintenance of chromosomes protein 4 (SMC-4) also known as chromosome-associated polypeptide C (CAP-C) or XCAP-C homolog is a protein that in humans is encoded by the ''SMC4'' gene. SMC-4 is a core subunit of condensin I and II, large protein complexes involved in high order chromosome organization, including condensation and segregation. SMC-4 protein is commonly associated with the SMC-2 protein, another protein complex within the SMC protein family. SMC-4 dimerizes with SMC-2, creating the flexible and dynamic structure of the condensin holocomplex. An over-expression of the SMC-4 protein is shown to impact carcinogenesis. Structure and interactions The primary 5 domain structure of SMC proteins is highly conserved among species. The basic structure of SMC proteins are characterized by a non-helical hinge group, separated by two anti-parallel α-helical coiled-coil domains, along with two Amino-terminal globular domains containing ATP hydrolytic sites, or nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SMC2
Structural maintenance of chromosomes protein 2 (SMC-2), also known as chromosome-associated protein E (CAP-E), is a protein that in humans is encoded by the ''SMC2'' gene. SMC2 is part of the SMC protein family and is a core subunit of condensin I and II, large protein complexes involved in chromosome condensation, overall organization. Several studies have demonstrated the necessity of SMC2 for cell division and proliferation. Structure As one of the 6 Eukaryotic SMC proteins, SMC2 forms a hetero dimer with SMC4 via their hinge domains. The heterodimer formed functions as a flexible and dynamic holocomplex core, which complexes with variant other non-SMC regulatory proteins to form condensin. In condensin I, SMC2 complexes with CAP-H, CAP-D2, and CAP-G. In condensin II, SMC2 complexes with CAP-H2, CAP-D3, and CAP-G2. Subunits CAP-H and CAP-H2 are categorized as kleisin proteins, similar to Scc1 which is found in cohesin, while CAP-D2, CAP-G, CAP-D3, and CAP-G2 contain str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condensin
Condensins are large protein complexes that play a central role in chromosome condensation and segregation during mitosis and meiosis (Figure 1). Their subunits were originally identified as major components of mitotic chromosomes assembled in ''Xenopus'' egg extracts. Subunit composition and phylogeny Eukaryotic types Many eukaryotic cells possess two different types of condensin complexes, known as condensin I and condensin II, each of which is composed of five subunits (Figure 2). Condensins I and II share the same pair of core subunits, SMC2 and SMC4, both belonging to a large family of chromosomal ATPases, known as SMC proteins (SMC stands for Structural Maintenance of Chromosomes). Each of the complexes contains a distinct set of non-SMC regulatory subunits (a kleisin subunit and a pair of HEAT repeat subunits). Both complexes are large, having a total molecular mass of 650-700 kDa. The core subunits condensins (SMC2 and SMC4) are conserved among all eukaryotic spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centromere
The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore. The physical role of the centromere is to act as the site of assembly of the kinetochores – a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation – i.e. binding microtubules and signaling to the cell cycle machinery when all chromosomes have adopted correct attachments to the spindle, so that it is safe for cell division to proceed to completion and for cells to enter anaphase. There are, broadly speaking, two types of centromeres. "Point centromeres" bind to specific proteins that recognize particular DNA sequences with high efficiency. Any piece of DNA with the point centromere DNA sequence on it will typically form a centr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KIF4A
Kinesin family member 4A is a protein that in humans is encoded by the ''KIF4A'' gene. Function Kinesins, such as KIF4A, are microtubule-based motor proteins that generate directional movement along microtubules. They are involved in many crucial cellular processes, including cell division. Interactions KIF4A has been shown to interact with HMG20B and DNMT3B. Clinical significance NTCP is the entry receptor for both Hepatitis B ( HBV) and Hepatitis D viruses ( HDV). KIF4 was found to play an essential role in HBV and HDV infection through its regulation of the retrograde transport of NTCP from the cytoplasm The cytoplasm describes all the material within a eukaryotic or prokaryotic cell, enclosed by the cell membrane, including the organelles and excluding the nucleus in eukaryotic cells. The material inside the nucleus of a eukaryotic cell a ... to the cell surface where it acts as a receptor for HBV/ HDV infection. References Further reading ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condensin
Condensins are large protein complexes that play a central role in chromosome condensation and segregation during mitosis and meiosis (Figure 1). Their subunits were originally identified as major components of mitotic chromosomes assembled in ''Xenopus'' egg extracts. Subunit composition and phylogeny Eukaryotic types Many eukaryotic cells possess two different types of condensin complexes, known as condensin I and condensin II, each of which is composed of five subunits (Figure 2). Condensins I and II share the same pair of core subunits, SMC2 and SMC4, both belonging to a large family of chromosomal ATPases, known as SMC proteins (SMC stands for Structural Maintenance of Chromosomes). Each of the complexes contains a distinct set of non-SMC regulatory subunits (a kleisin subunit and a pair of HEAT repeat subunits). Both complexes are large, having a total molecular mass of 650-700 kDa. The core subunits condensins (SMC2 and SMC4) are conserved among all eukaryotic spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
