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Beta-globin
Hemoglobin subunit beta (beta globin, β-globin, haemoglobin beta, hemoglobin beta) is a globin protein, coded for by the ''HBB'' gene, which along with alpha globin (HBA1, HBA), makes up the most common form of haemoglobin in adult humans, hemoglobin A (HbA). It is 147 amino acids long and has a molecular weight of 15,867 dalton (unit), Da. Normal adult human HbA is a tetrameric protein, heterotetramer consisting of two alpha chains and two beta chains. β-globin is encoded by the ''HBB'' gene on Chromosome 11 (human), human chromosome 11. Mutations in the gene produce several variants of the proteins which are implicated with genetic disorders such as sickle-cell disease and beta thalassemia, as well as beneficial traits such as genetic resistance to malaria. At least 50 disease-causing mutations in this gene have been discovered. Gene locus Beta-globin is produced by the gene ''HBB'' which is located in the multigene locus of Human β-globin locus, β-globin locus on Chr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HBG1
Hemoglobin subunit gamma-1 is a protein that in humans is encoded by the ''HBG1'' gene. Function The gamma globin genes (HBG1 and HBG2) are normally expressed in the fetal liver, spleen and bone marrow. Two gamma chains together with two alpha chains constitute fetal hemoglobin (HbF) which is normally replaced by adult hemoglobin (HbA) in the year following birth. In the non-pathological condition known as hereditary persistence of fetal hemoglobin (HPFH), gamma globin expression is continued into adulthood. Also, in cases of beta-thalassemia and related conditions, gamma chain production may be maintained, possibly as a mechanism to compensate for the mutated beta-globin. The two types of gamma chains differ at residue 136 where glycine is found in the G-gamma product (HBG2) and alanine is found in the A-gamma product (HBG1). The former is predominant at birth. The order of the genes in the beta-globin cluster is: 5' - HBE1, epsilon – HBG2, gamma-G – gamma-A – HBD, delta � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human β-globin Locus
The human β-globin locus is a cluster of genes located on chromosome 11. It is responsible for creating the β-chains found in hemoglobin. This cluster consists of 5 genes: ϵ, Gγ, Aγ, δ, and β genes, that respective order downstream. These genes are controlled by a locus control region (LCR) and are differentially expressed throughout development. Expression of these genes is regulated in embryonic erythropoiesis by many transcription factors, including KLF1, which is associated with the upregulation of Hemoglobin A, adult hemoglobin in adult definitive erythrocytes, and KLF2, which is vital to the expression of embryonic hemoglobin. Mechanism The human beta globin (HBB) Locus (genetics), locus is located on the short arm of chromosome 11 in an AT-rich region and is part of the olfactory receptor (OR) gene superfamily. The locus is crucial to the production of the β-globin chain of hemoglobin A (HbA), which, alongside the α-globin chain derived from the Hemoglobin subunit a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Point Mutation
A point mutation is a genetic mutation where a single nucleotide base is changed, inserted or deleted from a DNA or RNA sequence of an organism's genome. Point mutations have a variety of effects on the downstream protein product—consequences that are moderately predictable based upon the specifics of the mutation. These consequences can range from no effect (e.g. Synonymous substitution, synonymous mutations) to deleterious effects (e.g. frameshift mutations), with regard to protein production, composition, and function. Causes Point mutations usually take place during DNA replication. DNA replication occurs when one double-stranded DNA molecule creates two single strands of DNA, each of which is a template for the creation of the complementary strand. A single point mutation can change the whole DNA sequence. Changing one purine or pyrimidine may change the amino acid that the nucleotides code for. Point mutations may arise from spontaneous mutations that occur during DNA re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta Thalassemia
Beta-thalassemia (β-thalassemia) is an genetic disorder, inherited hemoglobinopathy, blood disorder, a form of thalassemia resulting in variable outcomes ranging from clinically asymptomatic to severe anemia individuals. It is caused by reduced or absent synthesis of the HBB, beta chains of hemoglobin, the molecule that carries oxygen in the blood. Symptoms depend on the extent to which hemoglobin is deficient, and include anemia, pallor, Fatigue, tiredness, Splenomegaly, enlargement of the spleen, jaundice, and Gallstone, gallstones. In severe cases death ensues. Beta thalassemia occurs due to a mutation of the HBB gene leading to deficient production of the hemoglobin subunit Hemoglobin subunit beta, beta-globin; the severity of the disease depends on the nature of the mutation, and whether or not the mutation is Zygosity, homozygous. The body's inability to construct beta-globin leads to reduced or zero production of Hemoglobin A, adult hemoglobin thus causing anemia. The ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin A
Hemoglobin A (HbA), also known as adult hemoglobin, hemoglobin A1 or α2β2, is the most common human hemoglobin tetramer, accounting for over 97% of the total red blood cell hemoglobin. Hemoglobin is an oxygen-binding protein, found in Red blood cell, erythrocytes, which transports oxygen from the lungs to the tissues. Hemoglobin A is the most common adult form of hemoglobin and exists as a tetramer containing two alpha subunits and two beta subunits (α2β2). Hemoglobin A2 (HbA2) is a less common adult form of hemoglobin and is composed of two alpha and two delta-globin subunits. This hemoglobin makes up 1-3% of hemoglobin in adults. Structure and function Hemoglobin A (HbA) is the most common adult form of hemoglobin and exists as a tetramer containing two alpha subunits and two beta subunits (α2β2). Each subunit contains a heme group that diatomic oxygen (O2) molecules can bind to. In addition to oxygen, subunit assembly and quaternary structure are known to play importa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Locus Control Region
A locus control region (LCR) is a long-range cis-regulatory element that enhances expression of linked genes at distal chromatin sites. It functions in a copy number-dependent manner and is tissue-specific, as seen in the selective expression of β-globin genes in erythroid cells. Expression levels of genes can be modified by the LCR and gene-proximal elements, such as promoters, enhancers, and silencers. The LCR functions by recruiting chromatin-modifying, coactivator, and transcription complexes. Its sequence is conserved in many vertebrates, and conservation of specific sites may suggest importance in function. It has been compared to a super-enhancer as both perform long-range ''cis'' regulation via recruitment of the transcription complex. History The β-globin LCR was identified over 20 years ago in studies of transgenic mice. These studies determined that the LCR was required for normal regulation of beta-globin gene expression. Evidence of the presence of this add ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HBE1
Hemoglobin subunit epsilon is a protein that in humans is encoded by the ''HBE1'' gene. Function The epsilon globin gene (HBE) is normally expressed in the embryonic yolk sac: two epsilon chains together with two zeta chains (an alpha-like globin) constitute the embryonic hemoglobin Hb Gower I; two epsilon chains together with two alpha chains form the embryonic Hb Gower II. Both of these embryonic hemoglobins are normally supplanted by fetal, and later, adult hemoglobin. The five beta-like globin genes are found within a 45 kb cluster on chromosome 11 in the following order: 5' - epsilon – gamma-G – gamma-A – delta – beta - 3'. See also *Hemoglobin * Human β-globin locus * Hemoglobin alpha chains (two genes, same sequence): ** ''HBA1'' ** ''HBA2 Hemoglobin, alpha 2 also known as ''HBA2'' is a gene that in humans codes for the alpha globin chain of hemoglobin. Function The human alpha globin gene cluster is located on chromosome 16 and spans about 30 kb, inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HBB Location
Hemoglobin subunit beta (beta globin, β-globin, haemoglobin beta, hemoglobin beta) is a globin protein, coded for by the ''HBB'' gene, which along with alpha globin ( HBA), makes up the most common form of haemoglobin in adult humans, hemoglobin A (HbA). It is 147 amino acids long and has a molecular weight of 15,867 Da. Normal adult human HbA is a heterotetramer consisting of two alpha chains and two beta chains. β-globin is encoded by the ''HBB'' gene on human chromosome 11. Mutations in the gene produce several variants of the proteins which are implicated with genetic disorders such as sickle-cell disease and beta thalassemia, as well as beneficial traits such as genetic resistance to malaria. At least 50 disease-causing mutations in this gene have been discovered. Gene locus Beta-globin is produced by the gene ''HBB'' which is located in the multigene locus of β-globin locus on chromosome 11, specifically on the short arm position 15.4. Expression of beta glob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemoglobin
Hemoglobin (haemoglobin, Hb or Hgb) is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin in the blood carries oxygen from the respiratory organs (lungs or gills) to the other tissues of the body, where it releases the oxygen to enable aerobic respiration which powers an animal's metabolism. A healthy human has 12to 20grams of hemoglobin in every 100mL of blood. Hemoglobin is a metalloprotein, a chromoprotein, and a globulin. In mammals, hemoglobin makes up about 96% of a red blood cell's dry weight (excluding water), and around 35% of the total weight (including water). Hemoglobin has an oxygen-binding capacity of 1.34mL of O2 per gram, which increases the total blood oxygen capacity seventy-fold compared to dissolved oxygen in blood plasma alone. The mammalian hemoglobin molecule can bind and transport up to four oxygen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sickle Cell Disease
Sickle cell disease (SCD), also simply called sickle cell, is a group of inherited Hemoglobinopathy, haemoglobin-related blood disorders. The most common type is known as sickle cell anemia. Sickle cell anemia results in an abnormality in the oxygen-carrying protein haemoglobin found in red blood cells. This leads to the red blood cells adopting an abnormal sickle-like shape under certain circumstances; with this shape, they are unable to deform as they pass through Capillary, capillaries, causing blockages. Problems in sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain (known as a sickle cell crisis) in joints, anemia, swelling in the hands and feet, bacterial infections, dizziness and stroke. The probability of severe symptoms, including long-term pain, increases with age. Without treatment, people with SCD rarely reach adulthood but with good healthcare, median life expectancy is between 58 and 66 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome 11 (human)
Chromosome 11 is one of the 23 pairs of chromosomes in humans. Humans normally have two copies of this chromosome. Chromosome 11 spans about 135 million base pairs (the building material of DNA) and represents between 4 and 4.5 percent of the total DNA in cells. The shorter arm (p arm) is termed 11p while the longer arm (q arm) is 11q. At about 21.5 genes per megabase, chromosome 11 is one of the most gene-rich, and disease-rich, chromosomes in the human genome. More than 40% of the 856 olfactory receptor genes in the human genome are located in 28 single-gene and multi-gene clusters along the chromosome. Gene Number of genes The following are some of the gene count estimates of human chromosome 11. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
