Pervasive Targeting of Nascent Transcripts by Hfq

Area of Science:

• Bacteriology
• Molecular Biology
• Genetics

Background:

• Hfq is a key bacterial RNA chaperone and post-transcriptional regulator.
• Understanding how Hfq interacts with RNA is crucial for deciphering bacterial gene regulation.

Purpose of the Study:

• To investigate the genome-wide binding sites of Hfq on nascent transcripts in Pseudomonas aeruginosa.
• To determine the relationship between Hfq and the post-transcriptional regulator Crc binding to nascent transcripts.
• To identify direct regulatory targets of Hfq and Crc.

Main Methods:

• Chromatin immunoprecipitation coupled with high-throughput DNA sequencing (ChIP-seq) was employed to map Hfq and Crc binding sites.
• Transcription inhibition was used to confirm co-transcriptional binding.
• Hfq dependency of Crc binding was assessed.

Main Results:

• Hfq was found to associate with hundreds of chromosomal regions in P. aeruginosa, predominantly on nascent transcripts.
• Crc was found to associate with many of the same nascent transcripts as Hfq.
• Crc association with these transcripts was dependent on Hfq.
• Direct regulatory targets of Hfq and Crc were uncovered.

Conclusions:

• Hfq binds to numerous transcripts co-transcriptionally in P. aeruginosa, often in conjunction with Crc.
• This study reveals direct regulatory targets of these RNA-binding proteins.
• The findings highlight a general method for studying RNA-binding protein interactions with nascent bacterial transcripts.
• Co-transcriptional binding of regulators to nascent mRNA may be a widespread mechanism for controlling bacterial translation.