Ribonuclease H2 subunit A, also known as RNase H2 subunit A, is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that in humans is encoded by the ''RNASEH2A''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
Function
The protein encoded by this gene is a component of the heterotrimeric type II
ribonuclease H
Ribonuclease H (abbreviated RNase H or RNH) is a family of non-sequence-specific endonuclease enzymes that catalyze the cleavage of RNA in an RNA/ DNA substrate via a hydrolytic mechanism. Members of the RNase H family can be found in nearly a ...
enzyme (RNaseH2). The other two subunits are the non-catalytic
RNASEH2B
Ribonuclease H2, subunit B is a protein that in humans is encoded by the ''RNASEH2B'' gene. RNase H2 is composed of a single catalytic subunit ( A) and two non-catalytic subunits (B and C), and degrades the RNA of RNA:DNA hybrids. The non-cataly ...
and
RNASEH2C
Ribonuclease H2 subunit C is a protein that in humans is encoded by the RNASEH2C gene.
Ribonuclease H, RNase H2 is composed of a single catalytic subunit (RNASEH2A, A) and two non-catalytic subunits (RNASEH2B, B and C), and degrades the RNA of R ...
. RNaseH2 is the major source of ribonuclease H activity in mammalian cells and endonucleolytically cleaves
ribonucleotide
In biochemistry, a ribonucleotide is a nucleotide containing ribose as its pentose component. It is considered a molecular precursor of nucleic acids. Nucleotides are the basic building blocks of DNA and RNA. Ribonucleotides themselves are basic m ...
s. It is predicted to remove
Okazaki fragment
Okazaki fragments are short sequences of DNA nucleotides (approximately 150 to 200 base pairs long in eukaryotes) which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA ...
RNA primers during lagging strand
DNA synthesis and to excise single ribonucleotides from DNA-DNA duplexes.
Clinical significance
Mutations in this gene cause
Aicardi–Goutières syndrome
Aicardi–Goutières syndrome (AGS), which is completely distinct from the similarly named Aicardi syndrome, is a rare, usually early onset childhood, inflammatory disorder most typically affecting the brain and the skin (neurodevelopmental disord ...
(AGS), an
autosomal recessive
In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...
neurological disorder characterized by progressive
microcephaly
Microcephaly (from New Latin ''microcephalia'', from Ancient Greek μικρός ''mikrós'' "small" and κεφαλή ''kephalé'' "head") is a medical condition involving a smaller-than-normal head. Microcephaly may be present at birth or it ...
and psychomotor retardation, intracranial calcifications, elevated levels of
interferon-alpha
The type-I interferons (IFN) are cytokines which play essential roles in inflammation, immunoregulation, tumor cells recognition, and T-cell responses. In the human genome, a cluster of thirteen functional IFN genes is located at the 9p21.3 cyto ...
and white blood cells in the
cerebrospinal fluid
Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates.
CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...
.
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Aicardi-Goutières Syndrome OMIM entries on Aicardi-Goutieres syndrome*
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