Question

What recognizes nonamer RSS to begin lymphocyte receptor rearrangement?

A. TdT
B. Artemis
C. RAG-1/2
D. XRCC4 with DNA ligase IV
E. Ku 70 and Ku 80

Answer 1

RAG-1/2 enzyme recognizes the nonamer RSS and initiates the recombination of gene segments in lymphocytes, which is crucial for generating diverse BCRs and TCRs for the immune response.

Step-by-step explanation:

The enzyme RAG-1/2 (Recombination Activating Gene 1 and 2) recognizes the nonamer recombination signal sequences (RSS) to begin lymphocyte receptor rearrangement. During B and T lymphocyte maturation, RAG-1/2 initiates the recombination of V (Variable), D (Diversity), and J (Joining) genetic segments.

This process is essential for the immune system to produce a diverse array of receptors, which enables the recognition of a vast array of antigens. The rearranged V-D-J and V-J gene segments encode the unique variable regions of B cell receptors (BCRs) and T cell receptors (TCRs), respectively, which are fundamental for the adaptive immune response.