Characterization of La Crosse virus small-genome transcripts

Area of Science:

• Virology
• Molecular Biology
• RNA Virus Replication

Background:

• La Crosse virus is a negative-strand RNA virus.
• Replication of negative-strand RNA viruses typically does not require host protein synthesis.
• The S genome segment encodes viral proteins.

Purpose of the Study:

• To investigate the requirements for La Crosse virus genome transcription and replication.
• To determine the initiation mechanism of La Crosse virus S mRNA.
• To understand the role of protein synthesis in viral RNA synthesis.

Main Methods:

• S1 nuclease mapping to locate the 3' end of S mRNA.
• Cycloheximide treatment to inhibit protein synthesis.
• Primer extension assays with chain-terminating nucleoside triphosphates to determine mRNA 5' end.

Main Results:

• Cycloheximide abolished genome replication, similar to other negative-strand RNA viruses.
• Cycloheximide also inhibited S mRNA synthesis, indicating a requirement for ongoing protein synthesis.
• La Crosse virus S mRNA appears to be initiated using a host primer.

Conclusions:

• Ongoing protein synthesis is essential for La Crosse virus genome transcription and replication.
• La Crosse virus transcription initiation differs from other negative-strand RNA viruses, suggesting host involvement.
• These findings present a novel mechanism for negative-strand RNA virus RNA synthesis.