Co-directional replication-transcription conflicts lead to replication restart.

Area of Science:

• Molecular Biology
• Genomics
• Microbiology

Background:

• DNA replication and transcription can conflict, especially on the lagging strand, potentially causing genomic instability.
• Genes are typically encoded on the leading strand for co-directional replication and transcription to minimize head-on conflicts.

Purpose of the Study:

• To investigate the in vivo consequences of co-directional transcription-replication encounters.
• To determine the role of replication restart proteins in resolving these conflicts in Bacillus subtilis.

Main Methods:

• Studied rapidly growing Bacillus subtilis cells.
• Observed associations of replicative helicase and replication restart proteins at conflict sites.
• Analyzed transcription-dependent protein recruitment.

Main Results:

• Co-directional transcription conflicts with replication in vivo, particularly at highly transcribed rRNA genes.
• Replication restart proteins and the replicative helicase are recruited in a transcription-dependent manner to sites of conflict.
• In vivo, replication restart machinery is essential for resolving both head-on and co-directional conflicts, unlike in vitro observations.

Conclusions:

• Co-directional transcription poses a significant challenge to DNA replication in vivo.
• The replication restart machinery plays a crucial role in resolving conflicts between transcription and replication in living cells.
• These findings explain the necessity of auxiliary proteins for replication restart and replisome progression.