RNA sequence and length contribute to RNA-induced conformational change of TLS/FUS

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Translocated in liposarcoma (TLS)/fused in sarcoma (FUS) is a DNA/RNA binding protein involved in cancer and neurodegenerative diseases.
• TLS is recruited to the CCND1 gene promoter upon DNA damage, interacting with promoter-associated non-coding RNA (pncRNA).
• A hypothesis suggests TLS binding to pncRNA induces a conformational change, inhibiting histone acetyltransferases and repressing CCND1 expression.

Purpose of the Study:

• To experimentally investigate the conformational change of TLS upon binding to pncRNA.
• To identify the specific RNA sequences and structural features of pncRNA critical for TLS conformational change.
• To explore if other nucleic acid targets also induce TLS conformational changes.

Main Methods:

• Fluorescence resonance energy transfer (FRET) was used to imply the closed-to-open conformational change of TLS.
• Truncation analysis of pncRNA was performed to determine the minimal functional fragment.
• RNA sequence analysis identified critical G-rich regions involved in the conformational change.

Main Results:

• A closed-to-open conformational change of TLS upon pncRNA binding was observed via FRET.
• A 31-nucleotide fragment of pncRNA was sufficient to induce TLS conformational change.
• A G-rich RNA sequence and RNA length were identified as critical factors for TLS conformational modulation.
• Telomeric DNA and telomeric repeat-containing RNA were also found to induce TLS conformational changes.

Conclusions:

• The study provides experimental evidence for the conformational change of TLS induced by pncRNA binding.
• Specific structural features of pncRNA, including a G-rich sequence and length, are essential for this conformational modulation.
• TLS conformational changes induced by various nucleic acid targets, including telomeric sequences, are likely fundamental to its biological functions.