Quantitative, super-resolution localization of small RNAs with sRNA-PAINT

Area of Science:

• Molecular Biology
• Plant Science
• Biotechnology

Background:

• Small RNAs are crucial non-coding RNAs in animals and plants, regulating gene expression.
• Their small size (21-24 nt) and diversity pose challenges for high-resolution detection and multiplexing.
• Existing methods lack the resolution and specificity needed for detailed analysis of small RNA localization and function.

Purpose of the Study:

• To develop a novel, high-resolution method for the in situ detection and quantification of multiple small RNAs simultaneously.
• To overcome the limitations of existing techniques in resolving and identifying small RNAs within complex biological samples.
• To create a user-friendly probe design tool to facilitate the application of the new method.

Main Methods:

• Developed sRNA-PAINT, combining DNA-PAINT super-resolution microscopy with locked nucleic acid (LNA) probes for enhanced specificity.
• Utilized qPAINT for accurate quantification and Exchange-PAINT for multiplexed detection of small RNAs.
• Created VARNISH (Vetting & Analysis of RNA for in situ Hybridization probes), an online tool for designing effective LNA-DNA probes.

Main Results:

• Achieved 20 nm resolution for small RNA detection, enabling visualization of individual molecules.
• Successfully detected and quantified small RNAs in specific cell layers of developing maize anthers.
• Demonstrated the capability of sRNA-PAINT for multiplexed analysis of small RNAs in plant reproductive tissues.

Conclusions:

• sRNA-PAINT is a powerful new method for high-resolution, multiplexed, and quantitative in situ detection of small RNAs.
• The VARNISH tool simplifies probe design, making sRNA-PAINT accessible for broader research applications.
• This technique provides unprecedented insights into small RNA roles in plant development, particularly in male reproduction.