Monoclonal antibodies to poly(adenosine diphosphate ribose) recognize different structures.

Area of Science:

• Biochemistry
• Molecular Biology
• Immunology

Background:

• Poly(adenosine diphosphate-ribose) [poly(ADP-Rib)] is a crucial post-translational modification involved in DNA repair and other cellular processes.
• Understanding the structural diversity of poly(ADP-Rib) is essential for elucidating its biological functions.
• Monoclonal antibodies offer specific tools for probing molecular structures.

Purpose of the Study:

• To generate and characterize monoclonal antibodies against poly(ADP-Rib).
• To investigate the distinct structural epitopes recognized by different anti-poly(ADP-Rib) antibodies.
• To differentiate between linear and branched structures within poly(ADP-Rib) molecules.

Main Methods:

• Hybridoma technology was employed to produce monoclonal antibodies.
• Antibody binding assays were performed using poly(ADP-Rib) preparations of varying sizes.
• Enzymatic hydrolysis (alkaline phosphomonoesterase and snake venom phosphodiesterase) was used to analyze antibody-protected sites.
• Inhibition assays with monomer units and poly(ADP-Rib) were conducted.

Main Results:

• Two monoclonal antibodies, 10H (IgG3) and 16B (IgM), were successfully established.
• Antibody 10H recognized linear poly(ADP-Rib) structures, with binding inhibited by monomer units.
• Antibody 16B recognized branched poly(ADP-Rib) structures, with binding unaffected by monomer units.

Conclusions:

• The study successfully generated two distinct monoclonal antibodies targeting different epitopes on poly(ADP-Rib).
• Antibody 10H specifically recognizes linear poly(ADP-Rib) chains, likely involving ribose-ribose linkages.
• Antibody 16B may recognize specific branched structures within poly(ADP-Rib) molecules, indicating structural heterogeneity.