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NEUROG3
Neurogenin-3 (NGN3) is a protein that in humans is encoded by the Neurog3 gene. Neurogenin-3 is a pro-endocrine transcription factor that is a member of the basic helix-loop-helix (bHLH) transcription factor and has a primary function of activating gene transcription in endocrine progenitor cells. It is a master regulator of pancreatic islet differentiation and regeneration and functions to directly enhance the expression of the lineage-committed transcription factors required for the differentiation of the endocrine progenitor cells into each of the endocrine cell subtypes. Expression Neurogenin3 is expressed in a small percentage of cells within the developing pancreas consisting of endocrine progenitor cells. It is expressed in the three stages of the development and differentiation of the endocrine pancreas. These stages are termed the # First or primary transition stage which involves the specification and growth of a primitive stalk of primarily undifferentiated pancreat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basic Helix–loop–helix
A basic helix–loop–helix (bHLH) is a protein structural motif that characterizes one of the largest families of dimerizing transcription factors. The word "basic" does not refer to complexity but to the chemistry of the motif because transcription factors in general contain basic amino acid residues in order to facilitate DNA binding. bHLH transcription factors are often important in development or cell activity. For one, BMAL1-Clock (also called ARNTL) is a core transcription complex in the molecular circadian clock. Other genes, like c-Myc and HIF-1, have been linked to cancer due to their effects on cell growth and metabolism. Structure The motif is characterized by two α-helices connected by a loop. In general, transcription factors (including this type) are dimeric, each with one helix containing basic amino acid residues that facilitate DNA binding. In general, one helix is smaller, and due to the flexibility of this loop, allows dimerization by folding and ... [...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 residue ... [...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 gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Islets Of Langerhands
The pancreatic islets or islets of Langerhans are the regions of the pancreas that contain its endocrine (hormone-producing) cells, discovered in 1869 by German pathological anatomist Paul Langerhans. The pancreatic islets constitute 1–2% of the pancreas volume and receive 10–15% of its blood flow. The pancreatic islets are arranged in density routes throughout the human pancreas, and are important in the metabolism of glucose. Structure There are about 1 million islets distributed throughout the pancreas of a healthy adult human, each of which measures an average of about 0.2 mm in diameter.:928 Each islet is separated from the surrounding pancreatic tissue by a thin fibrous connective tissue capsule which is continuous with the fibrous connective tissue that is interwoven throughout the rest of the pancreas.:928 Microanatomy Hormones produced in the pancreatic islets are secreted directly into the blood flow by (at least) five types of cells. In rat islets, endocrine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreatic Polypeptide
Pancreatic polypeptide (PP) is a polypeptide secreted by PP cells in the endocrine pancreas. It regulates pancreatic secretion activities, and also impacts liver glycogen storage and gastrointestinal secretion. Its secretion may be impacted by certain endocrine tumours. Gene The PPY gene encodes an unusually short protein precursor. This precursor is cleaved to produce pancreatic polypeptide, pancreatic icosapeptide, and a 5- to 7- amino-acid oligopeptide. Structure Pancreatic polypeptide consists of 36 amino acids. It has a molecular weight about 4200 Da. It has a similar structure to neuropeptide Y. Synthesis Pancreatic polypeptide is synthesised and secreted by PP cells (also known as gamma cells or F cells) of the pancreatic islets of the pancreas. These are found predominantly in the head of the pancreas. Function Pancreatic polypeptide regulates pancreatic secretion activities by both endocrine and exocrine tissues. It also affects hepatic glycogen levels and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucagon
Glucagon is a peptide hormone, produced by alpha cells of the pancreas. It raises concentration of glucose and fatty acids in the bloodstream, and is considered to be the main catabolic hormone of the body. It is also used as a Glucagon (medication), medication to treat a number of health conditions. Its effect is opposite to that of insulin, which lowers extracellular glucose. It is produced from proglucagon, encoded by the ''GCG'' gene. The pancreas releases glucagon when the amount of glucose in the bloodstream is too low. Glucagon causes the liver to engage in glycogenolysis: converting stored glycogen into glucose, which is released into the bloodstream. High blood-glucose levels, on the other hand, stimulate the release of insulin. Insulin allows glucose to be taken up and used by insulin-dependent tissues. Thus, glucagon and insulin are part of a feedback system that keeps blood glucose levels stable. Glucagon increases energy expenditure and is elevated under conditions of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulin
Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of glucose from the blood into liver, fat and skeletal muscle cells. In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats (triglycerides) via lipogenesis, or, in the case of the liver, into both. Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in the blood. Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is therefore an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules inside the cells. Low insulin levels in the blood have the opposite effect by promoting widespread catabolism, especially o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatostatin
Somatostatin, also known as growth hormone-inhibiting hormone (GHIH) or by several other names, is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G protein-coupled somatostatin receptors and inhibition of the release of numerous secondary hormones. Somatostatin inhibits insulin and glucagon secretion. Somatostatin has two active forms produced by the alternative cleavage of a single preproprotein: one consisting of 14 amino acids (shown in infobox to right), the other consisting of 28 amino acids. Among the vertebrates, there exist six different somatostatin genes that have been named ''SS1, SS2, SS3, SS4, SS5'' and ''SS6''. Zebrafish have all six. The six different genes, along with the five different somatostatin receptors, allow somatostatin to possess a large range of functions. Humans have only one somatostatin gene, ''SST''. Nomenclature Synonyms of "somatostatin" include: * growth hormoneâ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreatic Duct
The pancreatic duct, or duct of Wirsung (also, the major pancreatic duct due to the existence of an accessory pancreatic duct), is a duct joining the pancreas to the common bile duct. This supplies it with pancreatic juice from the exocrine pancreas, which aids in digestion. Structure The pancreatic duct joins the common bile duct just prior to the ampulla of Vater, after which both ducts perforate the medial side of the second portion of the duodenum at the major duodenal papilla. There are many anatomical variants reported, but these are quite rare. Accessory pancreatic duct Most people have just one pancreatic duct. However, some have an additional accessory pancreatic duct, also called the Duct of Santorini. An accessory pancreatic duct can be functional or non-functional. It may open separately into the second part of the duodenum,Moore KL, Dalley AF. 2006. Clinically Oriented Anatomy. 5th Ed. Lippincott Williams & Wilkins. p 287.1. Mchonde GJ, Gesase AP. Termination patt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISL1
Insulin gene enhancer protein ISL-1 is a protein that in humans is encoded by the ''ISL1'' gene. Function This gene encodes a transcription factor containing two N-terminal LIM domains and one C-terminal homeodomain. The encoded protein plays an important role in the embryogenesis of pancreatic islets of Langerhans. In mouse embryos, a deficiency of this gene results in failure to undergo neural tube motor neuron differentiation. Interactions ISL1 has been shown to interact with Estrogen receptor alpha. Role in cardiac development ISL1 is a marker for cardiac progenitors of the secondary heart field (SHF) which includes the right ventricle and the outflow tract. The biological function of ISL1 is demonstrated through ISL1 mutant mice and chick embryos that have altered cell proliferation, survival, and migration of cardiogenic precursors and severe cardiac defects. More recently it has been defined as a marker for a cardiac progenitor cell lineage that is capable of di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PAX6
Paired box protein Pax-6, also known as aniridia type II protein (AN2) or oculorhombin, is a protein that in humans is encoded by the ''PAX6'' gene. Function PAX6 is a member of the Pax gene family which is responsible for carrying the genetic information that will encode the Pax-6 protein. It acts as a "master control" gene for the development of eyes and other sensory organs, certain neural and epidermal tissues as well as other homologous structures, usually derived from ectodermal tissues. However, it has been recognized that a suite of genes is necessary for eye development, and therefore the term of "master control" gene may be inaccurate. Pax-6 is expressed as a transcription factor when neural ectoderm receives a combination of weak Sonic hedgehog (SHH) and strong TGF-Beta signaling gradients. Expression is first seen in the forebrain, hindbrain, head ectoderm and spinal cord followed by later expression in midbrain. This transcription factor is most noted for its u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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