Final answer:
True, immunoglobulin heavy-chain gene rearrangement promotes enhanced transcription of the μ-chain gene through the positioning of the promoter proximately to the enhancer elements, facilitating the VDJ and Cμ interaction for increased transcriptional activity.
Step-by-step explanation:
The statement in question concerns the process of immunoglobulin heavy-chain gene rearrangement, which is crucial for the development of the diversified antibody repertoire in B cells. This process involves the rearrangement of Variable (V), Diversity (D), and Joining (J) gene segments to form the unique variable region of the immunoglobulin heavy chain. Transcription of the μ-chain gene is accelerated as the promoter upstream of the VDJ region is positioned closer to the enhancer elements flanking the Cμ gene and the isotype switch signal sequence Sμ. This proximity facilitates the interaction between the promoter and enhancer elements, leading to increased transcriptional activity.
DNA recombinase plays a crucial role in this rearrangement by excising V, D, and J segments and facilitating their recombination. After successful rearrangement and the establishment of a functional B cell receptor (BCR), further genetic rearrangement can occur upon B cell activation, leading to class switching and the production of different antibody isotypes.