New Research Reveals Distinct Roles of Chromosome Organizers in Antibody Diversity
A study from Michigan State University, published in Nature Communications, has identified that two closely related chromosome-organizing proteins, STAG1 and STAG2, have distinct and opposing functions during the assembly of antibody genes.
Key Findings
- STAG2 acts as a molecular gatekeeper, preventing oversized DNA loops from forming too soon.
- STAG1 promotes the long-range DNA interactions necessary for assembling antibody genes.
- Without STAG2, STAG1 creates long DNA loops, allowing premature interactions of gene segments.
- STAG1 works with the CTCF protein to efficiently create long-range interactions.
- Later in antibody-gene assembly, both STAG1 and STAG2 work together to stitch V segments across long DNA stretches, enabling antibody diversity.
Context
Human antibodies start with identical DNA. Diversity arises by mixing V, D, and J segments through DNA looping via cohesin proteins. Defects in these proteins have been linked to developmental disorders and cancers.
Funding
National Institutes of Health (Grants R01AI155775 and R35GM153479), National Science Foundation (Grants DMS-2152011 and DBI-1942143), and Michigan State University Strategic Partnership Grant.