Sequence-specific high mobility group box factors recognize 10-12-base pair minor groove motifs

Area of Science:

• Molecular Biology
• Structural Biology
• Genetics

Background:

• High mobility group (HMG) box factors are sequence-specific DNA-binding proteins.
• These factors interact with DNA minor grooves, influencing DNA bending.
• Previous studies suggested HMG-DNA motifs are typically 6-8 base pairs.

Purpose of the Study:

• To investigate the precise DNA binding motifs for specific HMG box factors.
• To explore potential interactions beyond the canonical HMG domain.
• To understand the structural basis of extended DNA recognition by HMG factors.

Main Methods:

• Site selection assays to identify DNA binding motifs.
• DNA footprinting using deletion mutants.
• Three-dimensional Nuclear Magnetic Resonance (NMR) analyses.

Main Results:

• Identified a 12-base pair specific motif for Ste11 (AGAACAAAGAAA).
• Determined specific motifs for Tcf1 (12 bp), MatMc (12 bp), and Sox4 (10 bp).
• Discovered a novel interaction between Ste11 and the 3' end of the extended DNA motif, involving C-terminal amino acids.

Conclusions:

• HMG factors recognize specific DNA motifs longer than previously established.
• Interactions with extended DNA sequences, particularly at the 3' end, significantly contribute to HMG protein binding and DNA bending.
• Structural insights into HMG-DNA interactions are expanded by this research.