Occurrence and structure-function relationship of pentameric short sequence repeats in microbial genomes

Area of Science:

• Genomics
• Molecular Biology
• Microbiology

Background:

• Repetitive DNA is prevalent across all cellular life forms, including eukaryotes, archaea, and prokaryotes.
• While repetitive DNA constitutes large portions of eukaryotic genomes, its function remains largely unknown.
• In prokaryotes, slipped strand nucleotide mispairing (SSM) is a key mechanism driving repeat unit variation in repetitive DNA sequences.

Purpose of the Study:

• To review the existing literature on microbial short sequence repeats (SSRs) with five-nucleotide repeat units.
• To identify novel five-nucleotide SSRs and other potential SSRs in bacterial and archaeal genomes.
• To investigate the propensity and putative functions of these genetic elements.

Main Methods:

• Literature review focusing on microbial SSRs with five-nucleotide repeat units.
• Bioinformatic analysis of whole genome sequences from bacterial and archaeal species.
• Scanning for novel occurrences of five-nucleotide SSRs and other SSR types.

Main Results:

• Short sequence repeats (SSRs) are found in prokaryotes and are involved in gene expression regulation.
• SSRs can impact promoter strength and the integrity of open reading frames.
• Examples of functional five-nucleotide SSRs exist in bacteria like *Haemophilus influenzae*, *Neisseria gonorrhoeae*, and *Pasteurella haemolytica*.

Conclusions:

• Repetitive DNA, including SSRs, is a fundamental component of prokaryotic genomes with regulatory roles.
• Five-nucleotide SSRs represent a class of genetic switches with demonstrated functionality in bacteria.
• Further genomic analysis is needed to fully understand the prevalence and functions of SSRs in bacteria and archaea.