UBE3A

UBE3A is a human gene that provides instructions for making the enzyme ubiquitin protein ligase E3A. This enzyme is involved in targeting other proteins to be broken down (degraded) within cells. For example, the p53 protein, which controls cell growth and division, is one of the targets of ubiquitin protein ligase E3A. Protein degradation is a normal process that removes damaged or unnecessary proteins and helps maintain the normal functions of cells.

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Ubiquitin protein ligase 3A attaches a small protein called ubiquitin to proteins that should be degraded. Cellular structures called proteasomes recognize and digest proteins tagged with ubiquitin.

Both copies of the UBE3A gene are active in most of the body's tissues. In the brain, however, only the copy inherited from a person's mother (the maternal copy) is normally active.

The UBE3A gene is located on the long (q) arm of chromosome 15 between positions 11 and 13, from base pair 23,133,488 to base pair 23,235,220.

Related conditions

Mutations within the UBE3A gene are responsible for some cases of Angelman syndrome. Most of these mutations result in an abnormally short, nonfunctional version of ubiquitin protein ligase E3A. Because the copy of the gene inherited from a person's father (the paternal copy) is normally inactive in the brain, a mutation in the remaining maternal copy prevents any of the enzyme from being produced in the brain. This loss of enzyme function likely causes the characteristic features of Angelman syndrome.

Abnormalities involving the region of chromosome 15 that contains the UBE3A gene also cause Angelman syndrome. These chromosomal changes include deletions, rearrangements (translocations) of genetic material, and other abnormalities. Like mutations within the gene, these chromosomal changes prevent any functional ubiquitin protein ligase E3A from being produced in the brain.

References

• Bittel DC, Kibiryeva N, Talebizadeh Z, Driscoll DJ, Butler MG (2005). "Microarray analysis of gene/transcript expression in Angelman syndrome: deletion versus UPD". Genomics 85 (1): 85-91. PMID 15607424.
• Cassidy SB, Dykens E, Williams CA (2000). "Prader-Willi and Angelman syndromes: sister imprinted disorders". Am J Med Genet 97 (2): 136-46. PMID 11180221.
• Clayton-Smith J, Laan L (2003). "Angelman syndrome: a review of the clinical and genetic aspects". J Med Genet 40 (2): 87-95. PMID 12566516.
• Fang P, Lev-Lehman E, Tsai TF, Matsuura T, Benton CS, Sutcliffe JS, Christian SL, Kubota T, Halley DJ, Meijers-Heijboer H, Langlois S, Graham JM Jr, Beuten J, Willems PJ, Ledbetter DH, Beaudet AL (1999). "The spectrum of mutations in UBE3A causing Angelman syndrome". Hum Mol Genet 8 (1): 129-35. PMID 9887341.
• Moncla A, Malzac P, Livet MO, Voelckel MA, Mancini J, Delaroziere JC, Philip N, Mattei JF (1999). "Angelman syndrome resulting from UBE3A mutations in 14 patients from eight families: clinical manifestations and genetic counselling". J Med Genet 36 (7): 554-60. PMID 10424818.
• Williams CA (2005). "Neurological aspects of the Angelman syndrome". Brain Dev 27 (2): 88-94. PMID 15668046.