Robust mammalian RNA localization elements are complex and multipartite

Area of Science:

• Molecular Biology
• Cell Biology
• Neuroscience

Background:

• Subcellular RNA localization is vital for cellular function and is governed by specific regulatory elements within RNAs.
• While some RNA localization elements have been identified, their functional characteristics remain largely unknown.
• Previous work identified elements for kinesin-dependent RNA targeting to microtubule plus ends.

Purpose of the Study:

• To elucidate the critical characteristics of RNA localization elements necessary for their function.
• To determine the size, sequence requirements, and structural complexity of active RNA localization elements.

Main Methods:

• Systematic mutagenesis of RNA localization elements, creating tens of thousands of variants.
• Quantification of mutant element function in regulating subcellular RNA localization in neuronal cells.
• Single-molecule microscopy in primary rat neurons to validate findings.

Main Results:

• The minimally active size for these RNA localization elements is approximately 200 nucleotides.
• Elements contain multiple critical subsequences, some intolerant to any alteration, others tolerant to sequence shuffling but not compositional changes.
• Findings were validated in primary rat neurons using advanced microscopy techniques.

Conclusions:

• Highly active mammalian RNA localization elements are large, complex, and multipartite.
• These results provide a foundation for detailed mechanistic studies of RNA localization element function.
• Understanding these elements is key to deciphering RNA transport mechanisms in neurons and other cell types.