Transcript map of the temperate Lactobacillus gasseri bacteriophage phiadh

Area of Science:

• Molecular Biology
• Virology
• Genomics

Background:

• Bacteriophage phiadh exhibits lytic reproduction.
• Understanding phage transcription is crucial for viral replication studies.

Purpose of the Study:

• To analyze the temporal transcription of phage phiadh during its lytic cycle.
• To map phage phiadh gene expression regions and identify key transcripts.

Main Methods:

• Northern hybridizations were used to analyze phage phiadh transcripts.
• Phage genome was divided into early, middle, and late transcription regions.

Main Results:

• Eight overlapping transcript groups were identified, originating from common precursors.
• Early transcripts (10.9 kb) related to DNA replication were observed within 10 min.
• Middle transcripts (8.5 kb) involved in DNA packaging and cos site were seen at 30 min.
• Late transcripts (21.1 kb) encoding capsid morphogenesis and lysis functions appeared at 50 min.
• A separate late transcript group (3.2 kb) included repressor and integrase genes.
• Most transcripts persisted throughout the lytic cycle.

Conclusions:

• Phage phiadh transcription is temporally regulated, divided into distinct early, middle, and late phases.
• Specific genomic regions are responsible for replication, packaging, morphogenesis, and regulatory functions.
• Transcriptional persistence suggests stable expression of essential phage genes during lytic reproduction.