dsRNA formation leads to preferential nuclear export and gene expression.

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• Messenger RNAs (mRNAs) are exported from the nucleus to the cytoplasm for translation, mediated by export receptors like Mex67-Mtr2.
• The function of long non-coding RNAs (lncRNAs) in nuclear export remains largely unknown.
• Antisense RNAs (asRNAs) are a class of non-coding RNAs with emerging roles in gene regulation.

Purpose of the Study:

• To investigate the role of asRNAs in nuclear export and gene expression.
• To elucidate the mechanism by which asRNAs influence mRNA export.
• To understand the cellular significance of asRNA-mediated nuclear export.

Main Methods:

• Investigated the interaction between asRNAs, sense RNAs, and the helicase Dbp2 in Saccharomyces cerevisiae.
• Analyzed the export efficiency of single-stranded RNAs (ssRNAs) versus double-stranded RNAs (dsRNAs) mediated by the Mex67 export receptor.
• Assessed the impact of dsRNA degradation and formation prevention on cell viability.

Main Results:

• asRNAs anneal with their sense counterparts, forming dsRNAs that are preferentially exported from the nucleus.
• These dsRNAs exhibit higher affinity and capacity for the Mex67 export receptor compared to ssRNAs.
• The formation of dsRNA by asRNAs accelerates mRNA export and boosts gene expression.
• Interference with dsRNA formation or degradation is toxic to cells, highlighting its essential role.

Conclusions:

• asRNAs play a crucial role in enhancing gene expression by facilitating mRNA nuclear export.
• The formation of dsRNA is a key mechanism by which asRNAs promote cellular function.
• This mechanism explains the widespread occurrence and nuclear export of asRNAs, particularly during changing expression programs.