Rnaseh1 - ribonuclease H1

This gene encodes an endonuclease that specifically degrades the RNA of RNA-DNA hybrids and is necessary for DNA replication and repair. This enzyme is present in both mitochondria and nuclei, which are resulted from translation of a single mRNA with two in-frame initiation start codons. The use of the first start codon produces the mitochondrial isoform and the use of the second start codon produces the nuclear isoform. The production of the mitochondrial isoform is modulated by an upstream open reading frame (uORF) which encodes 7aa in mouse. An alternately spliced transcript variant has been found which is a candidate for nonsense-mediated mRNA decay (NMD). [provided by RefSeq, Nov 2013]