Exam 6: The Organization and Expression of Lymphocyte Receptor Genes

Dreyer and Bennett proposed that antibody heavy and light chains are encoded in two separate segments in the germ-line genome.At the time, what specifically was so revolutionary about this proposal?

Which of the following accounts for the transition from membrane-bound IgM to secreted IgM upon activation of a B cell?

What introduces single-strand break between V(D)J coding sequence and heptamer RSS?

Which protein(s) listed below is MOST directly responsible for joining gene segments during V(D)J recombination?

What closes the final nicks in the sugar-phosphate backbone to generate coding and signal joints?

Do you think, after reading this chapter, the statement that all human cells in an individual contain the same genome is true or false?

What introduces a transient hairpin that links the two strands in the V(D)J coding regions?

Can antibody diversity in humans be explained solely by V(D)J recombination? Why or why not?

Expression of RAG1 and RAG2 is tightly regulated.In addition to limiting the expression of RAG1 and RAG2 to select lymphocytes, can you describe a mechanism used to regulate the activity of RAG1 and RAG2 at the protein level?

What recognizes nonamer RSS to begin lymphocyte receptor rearrangement?

How many D ? -J ? rearrangements are possible in a normal human thymocyte?

Which of the following is used to generate diversity in the antibody repertoire?

Which of the following is NOT a means of generating diversity in the variable regions of the T-cell receptor genes?

Which of the following gene segments is NOT found in the mouse IgL loci?

Sequencing studies summarized in Figure 6-1 (in the text) demonstrate the existence of antibodies in which the same heavy chain variable region is associated with more than one heavy chain constant region.In your own words, in one sentence, describe the implication of this finding.