Ribonucleotide errors, RNase HII, and ribonucleotide excision repair

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Genomes are duplicated with high fidelity by DNA polymerases, but ribonucleoside monophosphates (rNMPs) are misincorporated at a higher rate than deoxyribonucleoside monophosphate (dNMP) errors.
• High intracellular concentrations of ribonucleoside triphosphates (rNTPs) favor rNMP misincorporation, making them the most common nucleotide requiring removal from genomic DNA.
• Failure to remove rNMPs leads to mutagenesis, neurological disorders, and embryonic lethality, highlighting the importance of cellular repair mechanisms.

Purpose of the Study:

• To review the mechanisms of ribonucleotide misincorporation by DNA polymerases.
• To discuss the roles of RNase H enzymes in recognizing and cleaving RNA-DNA hybrids.
• To provide a comprehensive overview of ribonucleotide excision repair (RER) pathways across eukaryotes, archaea, and bacteria.

Main Methods:

• Review of existing literature on DNA replication fidelity and error correction mechanisms.
• Analysis of biochemical pathways involved in ribonucleotide processing and repair.
• Comparative study of RER mechanisms across different domains of life.

Main Results:

• DNA polymerases exhibit a higher propensity for misincorporating rNMPs compared to dNMPs.
• RNase H enzymes are crucial for processing RNA-DNA hybrids, facilitating rNMP removal.
• Diverse RER pathways exist in eukarya, archaea, and bacteria to maintain genome integrity.

Conclusions:

• Ribonucleotide misincorporation is a common challenge to genome stability across all life forms.
• Ribonucleotide excision repair is an essential cellular process for preventing associated pathologies.
• Understanding these pathways provides insights into genome maintenance and evolution.