The forkhead DNA-binding domain binds specific G2-rich RNA sequences

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Transcription factors regulate gene expression by binding specific DNA sequences.
• The forkhead (FOX) transcription factor family utilizes a conserved forkhead domain (FHD) for DNA recognition.
• FOXL2 is a member of the FOX family implicated in various biological processes.

Purpose of the Study:

• To investigate the DNA-binding specificity of wild-type and oncogenic FOXL2.
• To explore the potential RNA-binding capabilities of FOXL2 and other FOX proteins.
• To identify target genes regulated by FOXL2 that may involve RNA interactions.

Main Methods:

• DNA and RNA PCR-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) were employed.
• Recombinant wild-type and C134W variant FOXL2 proteins were used.
• Gene expression analysis following FOXL2/Foxl2 knockdown was performed.

Main Results:

• FOXL2, including the oncogenic C134W variant, binds similar A-rich DNA sequences, indicating conserved DNA-binding specificity.
• FOXL2 demonstrates a significant preference for binding G2-rich RNA sequences over DNA.
• A subset of genes regulated by FOXL2 knockdown contains G2-rich sequences and is involved in critical cellular pathways.

Conclusions:

• The forkhead domain exhibits an unexpected ability to bind G2-rich RNA sequences.
• This novel RNA-binding characteristic of FOXL2 may represent a new mechanism of gene regulation.
• Further research is needed to elucidate the biological significance of FOXL2's RNA-binding activity.