High mobility group

High Mobility Group or HMG is a group of chromosomal proteins that help with
transcription, replication, recombination, and DNA repair.cite journal | author = Rajeswari MR, Jain A | title = High-mobility-group chromosomal proteins, HMGA1 as potential tumour markers | journal = Current Science | year = 2002 | pages = 838-844 | volume = 82 | issue = 7 | url = http://www.ias.ac.in/currsci/apr102002/838.pdf ]

Families

The HMG proteins are subdivided into 3 superfamilies each containing a characteristic functional domain:

* HMGA – contains an AT-hook domain
** HMGA1
** HMGA2

* HMGB – contains a HMG-box domain
** HMGB1
** HMGB2
** HMGB3
** HMGB4

* HMGN – contains a nucleosomal binding domain domain
** HMGN1 Protein
** HMGN2 Protein
** HMGN4 Protein

* Sex-Determining Region Y Protein

* TCF Transcription Factors
** Lymphoid enhancer-binding factor 1
** T Cell Transcription Factor 1

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.cite book | author = Johns EB | authorlink = | editor = | others = | title = The HMG chromosomal proteins | edition = | language = | publisher = Academic Press | location = Boston | year = 1982 | origyear = | pages = | quote = | isbn = 0-12-386050-4 | oclc = | doi = | url = | accessdate = ]

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 SRY 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.cite journal | author = Sitia G, Iannacone M, Müller S, Bianchi ME, Guidotti LG | title = Treatment with HMGB1 inhibitors diminishes CTL-induced liver disease in HBV transgenic mice | journal = J. Leukoc. Biol. | volume = 81 | issue = 1 | pages = 100–7 | year = 2007 | month = January | pmid = 16935945 | doi = 10.1189/jlb.0306173 | url = | issn = ]

ee also

*Transcription factors
*Gene regulatory network

References

External links

* [http://www.informatics.jax.org/mgihome/nomen/genefamilies/hmgfamily.shtml HMG nomenclature home page]
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