Human Anti-DNA/RNA G-quadruplex Recombinant Antibody (clone BG4) (CAT#: FAMAB-1862CQ)

Figure 1 Structure specificity of the BG4 antibody for G-quadruplex structures.

Binding curves as determined by ELISA showing that the BG4 antibody has high affinity for intramolecular and intermolecular DNA G-quadruplex structures with negligible binding to a RNA hairpin, double-stranded and single-stranded DNA. BG4 does not show a preference for any particular structural conformation, binding with similar affinity to parallel propeller (KIT1, KIT2 and MYC), anti-parallel (SPB1 and TBA), mixed parallel/anti-parallel propeller (hTELO) and intermolecular (intermolec hTELO) G-quadruplex structures.

Biffi, G., Tannahill, D., McCafferty, J., & Balasubramanian, S. (2013). Quantitative visualization of DNA G-quadruplex structures in human cells. Nature chemistry, 5(3), 182-186.

Figure 2 Visualization of DNA G-quadruplex structures in nuclei of human cancer cells

a, Immunofluorescence showing BG4 foci (red) in U2OS osteosarcoma cell nuclei. b, Loss of BG4 foci in U2OS cells after pre-incubation of the antibody with pre-folded G-quadruplex oligonucleotides. c, Loss of BG4 foci in U2OS cells after DNase I treatment. The dotted lines are the boundary of the nuclei. d, Increase in BG4 foci number after transfection with pre-folded G-quadruplex oligonucleotides. Nuclei are counterstained with DAPI (blue). Scale bars correspond to 20 μm.

Biffi, G., Tannahill, D., McCafferty, J., & Balasubramanian, S. (2013). Quantitative visualization of DNA G-quadruplex structures in human cells. Nature chemistry, 5(3), 182-186.

Figure 3 Visualization of G-quadruplex structures on human metaphase chromosomes.

Immunofluorescence for BG4 (red foci) on metaphase chromosomes prepared from HeLa cells. The large panel shows a general view of a metaphase spread, while the smaller panels show additional representative chromosomes. Arrows indicate examples of BG4 foci localized at chromosome ends. Chromosomes are counterstained with DAPI (blue). Scale bars correspond to 5 µm.

Biffi, G., Tannahill, D., McCafferty, J., & Balasubramanian, S. (2013). Quantitative visualization of DNA G-quadruplex structures in human cells. Nature chemistry, 5(3), 182-186.

Figure 4 Stabilization of endogenous G-quadruplex structures by a small molecule ligand.

a, Increase in BG4 foci number in U2OS cells after treatment with the G-quadruplex binding ligand pyridostatin (PDS). Nuclei are counterstained with DAPI (blue). Scale bar corresponds to 20 μm. b, Quantification of BG4 foci number per nucleus with or without PDS treatment. 200 nuclei were counted per condition and the standard error of the mean calculated from 3 replicates. After PDS treatment, a marked increase (~ 2.9-fold) in nuclear staining was observed. These results indicate that, at pertinent sites, PDS traps endogenous G-quadruplex structures to increase the number of BG4 targets available.

Biffi, G., Tannahill, D., McCafferty, J., & Balasubramanian, S. (2013). Quantitative visualization of DNA G-quadruplex structures in human cells. Nature chemistry, 5(3), 182-186.

Figure 5 Human Anti-DNA/RNA G-quadruplex Recombinant Antibody (clone BG4) in ELISA.

Binding curves as determined by ELISA showing that BG4 affinity for the telomeric DNA G-quadruplex hTELO is not affected by either prior incubation with pyridostatinbefore BG4 addition (PDS/BG4) or simultaneous addition of pyridostatin and BG4 (PDS+BG4). Dissociation constants (Kd) are indicated. The standard error of the mean was calculated from 3replicates.

Biffi, G., Tannahill, D., McCafferty, J., & Balasubramanian, S. (2013). Quantitative visualization of DNA G-quadruplex structures in human cells. Nature chemistry, 5(3), 182-186.