POLG Antibody – Rabbit Polyclonal

Mitochondrial DNA polymerase is heterotrimeric, consisting of a homodimer of accessory subunits plus a catalytic subunit. The protein encoded by this gene is the catalytic subunit of mitochondrial DNA polymerase. The encoded protein contains a polyglutamine tract near its N-terminus that may be polymorphic. Defects in this gene are a cause of progressive external ophthalmoplegia with mitochondrial DNA deletions 1 (PEOA1), sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO), Alpers-Huttenlocher syndrome (AHS), and mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE). Two transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Jul 2008]

POLG: Involved in the replication of mitochondrial DNA. Associates with mitochondrial DNA. Defects in POLG are the cause of progressive external ophthalmoplegia with mitochondrial DNA deletions autosomal dominant type 1 (PEOA1). Progressive external ophthalmoplegia is characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged- red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism. Defects in POLG are a cause of progressive external ophthalmoplegia with mitochondrial DNA deletions autosomal recessive (PEOB). PEOB is a severe form of progressive external ophthalmoplegia. It is clinically more heterogeneous than the autosomal dominant forms. Can be more severe. Defects in POLG are a cause of sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO). SANDO is a systemic disorder resulting from mitochondrial dysfunction associated with mitochondrial depletion in skeletal muscle and peripheral nerve tissue. The clinical triad of symptoms consists of sensory ataxic neuropathy, dysarthria, and ophthalmoparesis. However, the phenotype varies widely, even within the same family, and can also include myopathy, seizures, and hearing loss. An atypical form of the disease is characterized by headaches and/or seizures manifesting in childhood or adolescence, followed by development of cerebellar and sensory ataxia, dysarthria, progressive external ophthalmoplegia, and myoclonus in early adulthood. Defects in POLG are the cause of mitochondrial DNA depletion syndrome type 4A (MTDPS4A); also called Alpers diffuse degeneration of cerebral gray matter with hepatic cirrhosis. An autosomal recessive hepatocerebral syndrome. The typical course of the disease includes severe developmental delay, intractable seizures, liver failure, and death in childhood. Refractory seizures, cortical blindness, progressive liver dysfunction, and acute liver failure after exposure to valproic acid are considered diagnostic features. The neuropathological hallmarks are neuronal loss, spongiform degeneration, and astrocytosis of the visual cortex. Liver biopsy results show steatosis, often progressing to cirrhosis. Defects in POLG are the cause of mitochondrial DNA depletion syndrome type 4B (MTDPS4B); also known as mitochondrial DNA depletion syndrome 4B MNGIE type or mitochondrial neurogastrointestinal encephalopathy syndrome POLG- related. An autosomal recessive progressive multisystem disorder clinically characterized by chronic gastrointestinal dysmotility and pseudo-obstruction, cachexia, progressive external ophthalmoplegia, axonal sensory ataxic neuropathy, and muscle weakness. Defects in POLG are a cause of Leigh syndrome (LS). LS is a severe neurological disorder characterized by bilaterally symmetrical necrotic lesions in subcortical brain regions. Belongs to the DNA polymerase type-A family.

Protein type: EC 2.7.7.7; Transferase; DNA repair, damage; DNA replication; Mitochondrial

Chromosomal Location of Human Ortholog: 15q25

Cellular Component: gamma DNA polymerase complex; mitochondrion; mitochondrial inner membrane

Molecular Function: protein binding; DNA binding; protease binding; exonuclease activity; DNA-directed DNA polymerase activity; chromatin binding

Biological Process: base-excision repair, gap-filling; mitochondrial DNA replication; DNA-dependent DNA replication; DNA metabolic process; aging

Disease: Sensory Ataxic Neuropathy, Dysarthria, And Ophthalmoparesis; Mitochondrial Dna Depletion Syndrome 1 (mngie Type); Progressive External Ophthalmoplegia With Mitochondrial Dna Deletions, Autosomal Dominant, 1; Progressive External Ophthalmoplegia With Mitochondrial Dna Deletions, Autosomal Recessive; Mitochondrial Dna Depletion Syndrome 4b (mngie Type); Mitochondrial Dna Depletion Syndrome 4a (alpers Type)