Structure specific ds/ss-RNase activity in the extreme halophile Halobacterium salinarium

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Antisense RNA plays a role in gene regulation.
• Halobacterium salinarium utilizes a natural sense-antisense system for lytic transcript processing.
• Investigating RNA processing mechanisms in archaea provides insight into gene regulation.

Purpose of the Study:

• To investigate the in vivo ds/ss-RNA processing activity in Halobacterium salinarium.
• To determine the role of antisense RNA in gene regulation within this organism.
• To characterize the sequence specificity and requirements of the RNA processing activity.

Main Methods:

• Transformation of H. salinarium with a DNA construct encoding antisense RNA targeting phage phi H T4 transcript.
• Infection of transformed cells with phage phi H.
• Analysis of T4 transcript processing in transformed versus wild-type cells.

Main Results:

• Transformed H. salinarium cells expressing antisense RNA processed the T4 transcript upon phage infection.
• This processing mimicked the natural sense-antisense system's processing of the T1 transcript.
• T4 transcript processing was not observed in wild-type cells lacking the introduced antisense RNA.
• The observed RNA processing activity is dependent on the presence of an RNA duplex.

Conclusions:

• Antisense-RNA mediated gene regulation in H. salinarium involves a ds/ss-RNA processing activity.
• This activity is triggered by the formation of an RNA duplex.
• The processing mechanism is not sequence-specific, suggesting a general RNA processing capability activated by duplex formation.