Quantifying DNA-protein binding specificities by using oligonucleotide mass tags and mass spectroscopy.

Area of Science:

• Molecular Biology
• Genomics
• Biochemistry

Background:

• Understanding gene regulation requires knowledge of transcription factor (TF) binding affinities to DNA.
• Current methods for assessing DNA-TF binding specificities can be low-throughput and labor-intensive.

Purpose of the Study:

• To develop a general, multiplexed approach for quantifying DNA-TF binding specificities in vitro.
• To enable high-throughput analysis of TF binding relevant to gene regulation and disease.

Main Methods:

• Oligonucleotide mass tag (OMT) labeling of DNA binding sequences.
• Mass spectrometry-based quantification of OMT-labeled DNA fragments after TF binding.
• Utilizing the MassEXTEND platform for homogeneous, competitive binding assays.

Main Results:

• Successfully quantified binding specificities for up to 15 DNA sequences with the TF NF-kappaB P50 in a single assay.
• Multiplex assay results showed strong concordance with traditional gel shift assays.
• Demonstrated competitive binding of multiple DNA sequences to a TF in a homogeneous reaction.

Conclusions:

• The OMT labeling and mass spectrometry approach provides a scalable and efficient method for DNA-TF binding specificity analysis.
• This technique facilitates high-throughput applications, including genome-wide TF binding site mapping and SNP analysis in regulatory regions.
• Offers a powerful tool for comprehensive understanding of gene regulation mechanisms.