RNA-DNA hybrid ribonuclease activity

Definition

Target type: molecularfunction

Catalysis of the endonucleolytic cleavage of RNA in RNA-DNA hybrids to 5'-phosphomonoesters. [EC:3.1.26.4]

RNA-DNA hybrid ribonuclease activity involves the enzymatic hydrolysis of phosphodiester bonds within RNA molecules that are hybridized to DNA. This activity is crucial for several biological processes, including:

- **DNA repair:** RNA-DNA hybrids can form during DNA replication and repair processes, acting as substrates for these enzymes. Their degradation by RNA-DNA hybrid ribonucleases helps to maintain genomic integrity by removing aberrant RNA sequences that could interfere with DNA replication or repair.

- **Gene regulation:** RNA-DNA hybrids can form during transcription, and their presence can influence gene expression. RNA-DNA hybrid ribonucleases can regulate transcription by degrading these hybrids, thus modulating the level of gene expression.

- **Viral replication:** Some viruses, including retroviruses, use RNA-DNA hybrids as intermediates in their replication cycle. RNA-DNA hybrid ribonucleases can interfere with viral replication by degrading these hybrids, thus inhibiting viral growth.

- **Immune response:** RNA-DNA hybrids can also be involved in immune responses, as they can activate innate immune pathways. RNA-DNA hybrid ribonucleases can play a role in regulating these responses by degrading these hybrids and preventing excessive activation of the immune system.

- **Recombination and repair:** RNA-DNA hybrid ribonucleases participate in various DNA repair and recombination processes. For example, in homologous recombination, these enzymes can degrade invading RNA sequences to prevent aberrant recombination events.

The molecular mechanism of RNA-DNA hybrid ribonuclease activity involves the specific recognition and binding of RNA-DNA hybrids, followed by the hydrolysis of the phosphodiester bond within the RNA strand. The precise mechanism of substrate recognition and cleavage can vary depending on the specific enzyme, but typically involves the formation of a complex between the enzyme, the RNA-DNA hybrid, and divalent metal ions like magnesium.

The activity of RNA-DNA hybrid ribonucleases is tightly regulated to ensure proper cellular function. These enzymes are often expressed in a tissue-specific manner, and their activity can be modulated by various factors, including post-translational modifications, interactions with other proteins, and cellular stress responses.

Disruptions in RNA-DNA hybrid ribonuclease activity can have significant consequences for cellular health and have been linked to various diseases, including cancer, autoimmune disorders, and viral infections.'
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Proteins (4)

Compounds (27)