Developmental expression of non-coding RNAs in Chlamydia trachomatis during normal and persistent growth

Area of Science:

• Microbiology
• Bacterial Pathogenesis
• RNA Biology

Background:

• Chlamydia trachomatis displays a biphasic developmental cycle.
• This cycle can be altered into a persistent state by host factors like IFN-γ and antibiotics (β-lactams).
• The role of non-coding RNAs (ncRNAs) in Chlamydia's developmental cycle and persistence is largely unknown.

Purpose of the Study:

• To identify and characterize novel ncRNAs in Chlamydia trachomatis.
• To investigate the differential expression of these ncRNAs during the normal developmental cycle, induced persistence, and reactivation.
• To determine the regulatory function of identified ncRNAs.

Main Methods:

• Identification of ncRNAs using intergenic tiling microarrays.
• Confirmation and expression analysis via northern blotting.
• RNA 5' and 3' end determination using RNA circularization.
• Promoter prediction analysis.
• Functional analysis using a heterologous co-expression system.

Main Results:

• A family of differentially expressed ncRNAs was identified.
• Expression patterns varied significantly during the normal developmental cycle, IFN-γ-induced persistence, and carbenicillin-induced persistence.
• Eight ncRNAs possessed non-templated 3'-poly-A or poly-AG additions.
• One identified ncRNA was shown to regulate FtsI expression by inducing ftsI mRNA degradation.

Conclusions:

• Chlamydia trachomatis expresses a diverse set of ncRNAs with dynamic expression patterns.
• These ncRNAs are differentially regulated during developmental transitions and stress-induced persistence.
• At least one ncRNA plays a regulatory role in bacterial gene expression, impacting essential processes like cell division.