TWNK Antibody – Rabbit Polyclonal

This gene encodes a hexameric DNA helicase which unwinds short stretches of double-stranded DNA in the 5' to 3' direction and, along with mitochondrial single-stranded DNA binding protein and mtDNA polymerase gamma, is thought to play a key role in mtDNA replication. The protein localizes to the mitochondrial matrix and mitochondrial nucleoids. Mutations in this gene cause infantile onset spinocerebellar ataxia (IOSCA) and progressive external ophthalmoplegia (PEO) and are also associated with several mitochondrial depletion syndromes. Alternative splicing results in multiple transcript variants encoding distinct isoforms.[provided by RefSeq, Aug 2009]

PEO1: Involved in mitochondrial DNA (mtDNA) metabolism. Could function as an adenine nucleotide-dependent DNA helicase. Function inferred to be critical for lifetime maintenance of mtDNA integrity. In vitro, forms in combination with POLG, a processive replication machinery, which can use double-stranded DNA (dsDNA) as template to synthesize single-stranded DNA (ssDNA) molecules. May be a key regulator of mtDNA copy number in mammals. Defects in PEO1 are the cause of progressive external ophthalmoplegia with mitochondrial DNA deletions autosomal dominant type 3 (PEOA3). 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 PEO1 are a cause of sensory ataxic neuropathy dysarthria and ophthalmoparesis (SANDO). SANDO is a clinically heterogeneous systemic disorder with variable features resulting from mitochondrial dysfunction. It shares phenotypic characteristics with autosomal recessive progressive external ophthalmoplegia and mitochondrial neurogastrointestinal encephalopathy syndrome. The clinical triad of symptoms consists of sensory ataxic, neuropathy, dysarthria, and ophthalmoparesis. Defects in PEO1 are the cause of mitochondrial DNA depletion syndrome type 7 (MTDPS7); also known as spinocerebellar ataxia infantile-onset (IOSCA). A severe disease associated with mitochondrial dysfunction. Some patients are affected by progressive atrophy of the cerebellum, brain stem, the spinal cord, and sensory axonal neuropath. Clinical features include hypotonia, athetosis, ataxia, ophthalmoplegia, sensorineural hearing deficit, sensory axonal neuropathy, epileptic encephalopathy and female hypogonadism. Some individuals manifest a hepatocerebral phenotype characterized by liver insufficiency, increased serum and CSF lactate, hypotonia, psychomotor retardation and peripheral neuropathy. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: EC 3.6.4.12; DNA replication; Mitochondrial; Helicase

Chromosomal Location of Human Ortholog: 10q24

Cellular Component: mitochondrial matrix

Molecular Function: protease binding; 5'-3' DNA helicase activity; ATP binding; single-stranded DNA binding

Biological Process: DNA unwinding during replication; mitochondrion organization and biogenesis; organelle organization and biogenesis; mitochondrial DNA replication; protein homooligomerization; transcription from mitochondrial promoter

Disease: Perrault Syndrome 5; Sensory Ataxic Neuropathy, Dysarthria, And Ophthalmoparesis; Mitochondrial Dna Depletion Syndrome 7 (hepatocerebral Type); Progressive External Ophthalmoplegia With Mitochondrial Dna Deletions, Autosomal Dominant, 3