High mobility group
Encyclopedia
High-Mobility Group or HMG is a group of chromosomal protein
s that help with
transcription
, replication
, recombination
, and DNA repair
.
Proteins containing any of these embedded in their sequence are known as HMG motif proteins.
HMG-box
proteins are found in a variety of eukaryotic organisms.
They were originally isolated from mammalian cells, and named according to their electrophoretic mobility in polyacrylamide
gels.
gene on the Y Chromosome, responsible for male sexual differentiation, contains an HMG-Box domain. Recently, a member of the HMG family of proteins, HMGB1
, has been shown to have an extracellular activity as a chemokine
, attracting neutrophils and mononuclear inflammatory cells to the infected liver
.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
s that help with
transcription
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
, replication
DNA replication
DNA replication is a biological process that occurs in all living organisms and copies their DNA; it is the basis for biological inheritance. The process starts with one double-stranded DNA molecule and produces two identical copies of the molecule...
, recombination
Genetic recombination
Genetic recombination is a process by which a molecule of nucleic acid is broken and then joined to a different one. Recombination can occur between similar molecules of DNA, as in homologous recombination, or dissimilar molecules, as in non-homologous end joining. Recombination is a common method...
, and DNA repair
DNA repair
DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many as 1...
.
Families
The HMG proteins are subdivided into 3 superfamilies each containing a characteristic functional domain:- HMGAHMGAHMGA is a family of high mobility group proteins characterized by an AT-hook. They code for a "small, nonhistone, chromatin-associated protein that has no intrinsic transcriptional activity but can modulate transcription by altering the chromatin architecture".A recent study has shown variations in...
– contains an AT-hookAT-hookright|thumb|The second AT-hook of [[HMGA1]] bound to the minor-groove of AT-rich DNA. The amino-acid side chains and nucleotides have been hidden....
domain- HMGA1HMGA1High-mobility group protein HMG-I/HMG-Y is a protein that in humans is encoded by the HMGA1 gene.Mice lacking their variant of HMGA1, i.e., Hmga1-/- mice, are diabetic and express low levels of the insulin receptor.-Interactions:...
- HMGA2HMGA2High-mobility group AT-hook 2, also known as HMGA2, is a protein that, in humans, is encoded by the HMGA2 gene.- Function :This gene encodes a protein that belongs to the non-histone chromosomal high-mobility group protein family. HMG proteins function as architectural factors and are essential...
- HMGA1
- HMGB – contains a HMG-boxHMG-boxThe HMG-box is a protein domain which is involved in DNA binding.-Structure:The structure of the HMG-box domain contains three alpha helices separated by loops .-Function:...
domain- HMGB1HMGB1High-mobility group protein B1, also known as high-mobility group protein 1 and amphoterin, is a protein that in humans is encoded by the HMGB1 gene.HMG-1 belongs to high mobility group.-Role in Inflammation:...
- HMGB2HMGB2High-mobility group protein B2 also known as high-mobility group protein 2 is a protein that in humans is encoded by the HMGB2 gene.- Function :...
- HMGB3HMGB3High-mobility group protein B3 is a protein that in humans is encoded by the HMGB3 gene....
- HMGB4HMGB4High mobility group protein B4 is a transcription factor that in humans is encoded by the HMGB4 gene....
- HMGB1
- HMGNHMGNThe term HMGN stands for High Mobility Group Nucleosome-binding. HMGN proteins are members of the broader class of High mobility group chromosomal proteins that help in transcription, replication, recombination, and DNA repair....
– contains a nucleosomal binding domainHigh mobility group protein HMG14 and HMG17High mobility group protein HMG14 and HMG17 also known as nucleosomal binding domain is a family of evolutionarily related proteins.High mobility group proteins constitute a family of relatively low molecular weight non-histone components in chromatin...
domain- HMGN1HMGN1Non-histone chromosomal protein HMG-14 is a protein that in humans is encoded by the HMGN1 gene.-Further reading:...
- HMGN2HMGN2Non-histone chromosomal protein HMG-17 is a protein that in humans is encoded by the HMGN2 gene.-Further reading:...
- HMGN3HMGN3High mobility group nucleosome-binding domain-containing protein 3 is a protein that in humans is encoded by the HMGN3 gene.-External links:...
- HMGN4HMGN4High mobility group nucleosome-binding domain-containing protein 4 is a transcription factor that in humans is encoded by the HMGN4 gene.- Function :...
- HMGN1
- Sex-Determining Region Y ProteinSRYSRY is a sex-determining gene on the Y chromosome in the therians .This intronless gene encodes a transcription factor that is a member of the SOX gene family of DNA-binding proteins...
- TCF Transcription Factors
- Lymphoid enhancer-binding factor 1Lymphoid enhancer-binding factor 1Lymphoid enhancer-binding factor 1 is a protein that in humans is encoded by the LEF1 gene.- Function :Lymphoid enhancer-binding factor-1 is a 48-kD nuclear protein that is expressed in pre-B and T cells. It binds to a functionally important site in the T-cell receptor-alpha enhancer and confers...
- T Cell Transcription Factor 1
- Lymphoid enhancer-binding factor 1
Proteins containing any of these embedded in their sequence are known as HMG motif proteins.
HMG-box
HMG-box
The HMG-box is a protein domain which is involved in DNA binding.-Structure:The structure of the HMG-box domain contains three alpha helices separated by loops .-Function:...
proteins are found in a variety of eukaryotic organisms.
They were originally isolated from mammalian cells, and named according to their electrophoretic mobility in polyacrylamide
Polyacrylamide
Polyacrylamide is a polymer formed from acrylamide subunits. It can be synthesized as a simple linear-chain structure or cross-linked, typically using N,N-methylenebisacrylamide. Polyacrylamide is not toxic...
gels.
Function
HMG proteins are thought to play a significant role in various human disorders. Disruptions and rearrangements in the genes coding for some of the HMG proteins are associated with some common benign tumors. Antibodies to HMG proteins are found in patients suffering from autoimmune diseases. The SRYSRY
SRY is a sex-determining gene on the Y chromosome in the therians .This intronless gene encodes a transcription factor that is a member of the SOX gene family of DNA-binding proteins...
gene on the Y Chromosome, responsible for male sexual differentiation, contains an HMG-Box domain. Recently, a member of the HMG family of proteins, HMGB1
HMGB1
High-mobility group protein B1, also known as high-mobility group protein 1 and amphoterin, is a protein that in humans is encoded by the HMGB1 gene.HMG-1 belongs to high mobility group.-Role in Inflammation:...
, has been shown to have an extracellular activity as a chemokine
Chemokine
Chemokines are a family of small cytokines, or proteins secreted by cells. Their name is derived from their ability to induce directed chemotaxis in nearby responsive cells; they are chemotactic cytokines...
, attracting neutrophils and mononuclear inflammatory cells to the infected liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
.