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Polycomb
Polycomb-group proteins (PcG proteins) are a family of protein complexes first discovered in fruit flies that can remodel chromatin such that epigenetic silencing of genes takes place. Polycomb-group proteins are well known for silencing Hox genes through modulation of chromatin structure during embryonic development in fruit flies (''Drosophila melanogaster''). They derive their name from the fact that the first sign of a decrease in PcG function is often a homeotic transformation of posterior legs towards anterior legs, which have a characteristic comb-like set of bristles. In insects In ''Drosophila'', the Trithorax-group (trxG) and Polycomb-group (PcG) proteins (They derive their name from the fact that the first sign of a decrease in PcG function is often a homeotic transformation of posterior legs towards anterior legs, which have a characteristic comb-like set of bristles) act antagonistically and interact with chromosomal elements, termed Cellular Memory Modules (CMMs). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BMI1
Polycomb complex protein BMI-1 also known as polycomb group RING finger protein 4 (PCGF4) or RING finger protein 51 (RNF51) is a protein that in humans is encoded by the ''BMI1'' gene (B cell-specific Moloney murine leukemia virus integration site 1). BMI1 is a polycomb ring finger oncogene. Function BMI1 (B lymphoma Mo-MLV insertion region 1 homolog) has been reported as an oncogene by regulating p16 and p19, which are cell cycle inhibitor genes. Bmi1 knockout in mice results in defects in hematopoiesis, skeletal patterning, neurological functions, and development of the cerebellum. Recently it has been reported that BMI1 is rapidly recruited to sites of DNA damage, where it sustains for over 8h. Loss of BMI1 leads to radiation sensitive and impaired repair of DNA double-strand breaks by homologous recombination. Bmi1 is necessary for efficient self-renewing cell divisions of adult hematopoietic stem cells as well as adult peripheral and central nervous system neural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PHC1
Polyhomeotic-like protein 1 is a protein that in humans is encoded by the ''PHC1'' gene. Function This gene is a homolog of the ''Drosophila'' polyhomeotic gene, which is a member of the Polycomb group of genes. The gene product is a component of a multimeric protein complex that contains EDR2 and the vertebrate Polycomb protein BMI1. The gene product, the EDR2 protein, and the ''Drosophila'' polyhomeotic protein share two highly conserved domains, named homology domains I and II. These domains are involved in protein–protein interactions and may mediate heterodimerization of the protein encoded by this gene and the EDR2 protein. Mutations in this gene have been associated to cases of primary microcephaly. Interactions PHC1 has been shown to interact Advocates for Informed Choice, doing business as, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycomb Group Proteins And Cancer
Polycomb-group proteins (PcG proteins) are a family of protein complexes first discovered in fruit flies that can remodel chromatin such that epigenetic silencing of genes takes place. Polycomb-group proteins are well known for silencing Hox genes through modulation of chromatin structure during embryonic development in fruit flies (''Drosophila melanogaster''). They derive their name from the fact that the first sign of a decrease in PcG function is often a homeotic transformation of posterior legs towards anterior legs, which have a characteristic comb-like set of bristles. In insects In ''Drosophila'', the Trithorax-group (trxG) and Polycomb-group (PcG) proteins (They derive their name from the fact that the first sign of a decrease in PcG function is often a homeotic transformation of posterior legs towards anterior legs, which have a characteristic comb-like set of bristles) act antagonistically and interact with chromosomal elements, termed Cellular Memory Modules (CMMs). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PRC2
PRC2 (polycomb repressive complex 2) is one of the two classes of polycomb-group proteins or (PcG). The other component of this group of proteins is PRC1 ( Polycomb Repressive Complex 1). This complex has histone methyltransferase activity and primarily methylates histone H3 on lysine 27 (i.e. H3K27me3), a mark of transcriptionally silent chromatin. PRC2 is required for initial targeting of genomic region (PRC Response Elements or PRE) to be silenced, while PRC1 is required for stabilizing this silencing and underlies cellular memory of silenced region after cellular differentiation. PRC1 also mono-ubiquitinates histone H2A on lysine 119 (H2AK119Ub1). These proteins are required for long term epigenetic silencing of chromatin and have an important role in stem cell differentiation and early embryonic development. PRC2 are present in most multicellular organisms. The mouse PRC2 has four subunits: Suz12 (zinc finger), Eed, Ezh1 or Ezh2 (SET domain with histone methyltransfe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PHC2
Polyhomeotic-like protein 2 is a protein that in humans is encoded by the ''PHC2'' gene. Function In Drosophila melanogaster, the 'Polycomb' group (PcG) of genes are part of a cellular memory system that is responsible for the stable inheritance of gene activity. PcG proteins form a large multimeric, chromatin-associated protein complex. The protein encoded by this gene has homology to the Drosophila PcG protein 'polyhomeotic' (Ph) and is known to heterodimerize with EDR1 and colocalize with BMI1 in interphase nuclei of human cells. The specific function in human cells has not yet been determined. Two transcript variants encoding different isoforms have been found for this gene. Interactions PHC2 has been shown to interact with MAPKAPK2, PHC1, BMI1 and MCRS1 Microspherule protein 1 is a protein that in humans is encoded by the ''MCRS1'' gene. Interactions MCRS1 has been shown to interact with PHC2, Death associated protein 6, NOL1, PINX1 and Telomerase reverse transc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trithorax-group Proteins
Trithorax-group proteins (TrxG) are a heterogeneous collection of proteins whose main action is to maintain gene expression. They can be categorized into three general classes based on molecular function: # histone-modifying TrxG proteins # chromatin-remodeling TrxG proteins # DNA-binding TrxG proteins, plus other TrxG proteins not categorized in the first three classes. Discovery The founding member of TrxG proteins, trithorax (trx), was discovered ~1978 by Philip Ingham as part of his doctoral thesis while a graduate student in the laboratory of J.R.S. Whittle at the University of Sussex. Histone-lysine ''N''-methyltransferase 2A is the human homolog of trx. The table contains names of Drosophila TrxG members. Homologs in other species may have different names. Function Trithorax-group proteins typically function in large complexes formed with other proteins. The complexes formed by TrxG proteins are divided into two groups: histone-modifying complexes and ATP-depend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycomb Recruitment In X Chromosome Inactivation
X chromosome inactivation (XCI) is the phenomenon that has been selected during the evolution to balance X-linked gene dosage between XX females and XY males. Phases XCI is usually divided in two phases, the establishment phase when gene silencing is reversible, and maintenance phase when gene silencing becomes irreversible. During the establishment phase of X Chromosome Inactivation (XCI), Xist RNA, the master regulator of this process, is monoallelically upregulated and it spreads ''in cis'' along the future inactive X (Xi), relocates to the nuclear periphery. and recruits repressive chromatin-remodelling complexes Among these, Xist recruits proteins of the Polycomb repressive complexes. Whether Xist directly recruits Polycomb repressive complex 2 (PRC2) to the chromatin or this recruitment is the consequence of Xist-mediated changes on the chromatin has been object of intense debate. Mechanism Some studies showed that PRC2 components are not associated with Xist RNA ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vernalization
Vernalization (from Latin ''vernus'', "of the spring") is the induction of a plant's flowering process by exposure to the prolonged cold of winter, or by an artificial equivalent. After vernalization, plants have acquired the ability to flower, but they may require additional seasonal cues or weeks of growth before they will actually flower. The term is sometimes used to refer to the need of herbal (non-woody) plants for a period of cold dormancy in order to produce new shoots and leaves, but this usage is discouraged. Many plants grown in temperate climates require vernalization and must experience a period of low winter temperature to initiate or accelerate the flowering process. This ensures that reproductive development and seed production occurs in spring and winters, rather than in autumn. The needed cold is often expressed in chill hours. Typical vernalization temperatures are between 1 and 7 degrees Celsius (34 and 45 degrees Fahrenheit). For many perennial plants, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physcomitrella Patens
''Physcomitrium patens'', (synonym: ''Physcomitrella patens'' ) the spreading earthmoss, is a moss (bryophyte) used as a model organism for studies on plant evolution, development, and physiology. Distribution and ecology ''Physcomitrella patens'' is an early colonist of exposed mud and earth around the edges of pools of water. ''P. patens'' has a disjunct distribution in temperate parts of the world, with the exception of South America. The standard laboratory strain is the "Gransden" isolate, collected by H. Whitehouse from Gransden Wood, in Cambridgeshire in 1962. Model organism Mosses share fundamental genetic and physiological processes with vascular plants, although the two lineages diverged early in land-plant evolution. A comparative study between modern representatives of the two lines may give insight into the evolution of mechanisms that contribute to the complexity of modern plants. In this context, ''P. patens'' is used as a model organism. ''P. p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Embryonic Development
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm cell. The resulting fusion of these two cells produces a single-celled zygote that undergoes many cell divisions that produce cells known as blastomeres. The blastomeres are arranged as a solid ball that when reaching a certain size, called a morula, takes in fluid to create a cavity called a blastocoel. The structure is then termed a blastula, or a blastocyst in mammals. The mammalian blastocyst hatches before implantating into the endometrial lining of the womb. Once implanted the embryo will continue its development through the next stages of gastrulation, neurulation, and organogenesis. Gastrulation is the formation of the three germ layers that will form all of the different parts of the body. Neurulation forms the nervous s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalent Chromatin
Bivalent chromatin are segments of DNA, bound to histone proteins, that have both repressing and activating epigenetic regulators in the same region. These regulators work to enhance or silence the expression of genes. Since these regulators work in opposition to each other, they normally interact with chromatin at different times. However, in bivalent chromatin, both types of regulators are interacting with the same domain at the same time. Bivalent chromatin domains are normally associated with promoters of transcription factor genes that are expressed at low levels. Bivalent domains have also been found to play a role in developmental regulation in pluripotent embryonic stems cells, gene imprinting and cancer. Bivalent epigenetic regulators The most common antagonistic epigenetic regulators found together on bivalent chromatin domains are methylation marks on histone 3 lysine 4 (H3K4me3) and histone 3 lysine 27 (H3K27me3). The H3K27me3 mark silences the gene while the H3K4me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epigenetic
In biology, epigenetics is the study of stable phenotypic changes (known as ''marks'') that do not involve alterations in the DNA sequence. The Greek prefix '' epi-'' ( "over, outside of, around") in ''epigenetics'' implies features that are "on top of" or "in addition to" the traditional genetic basis for inheritance. Epigenetics most often involves changes that affect the regulation of gene expression, but the term can also be used to describe any heritable phenotypic change. Such effects on cellular and physiological phenotypic traits may result from external or environmental factors, or be part of normal development. The term also refers to the mechanism of changes: functionally relevant alterations to the genome that do not involve mutation of the nucleotide sequence. Examples of mechanisms that produce such changes are DNA methylation and histone modification, each of which alters how genes are expressed without altering the underlying DNA sequence. Gene express ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
