Explain the part played by transcription factors in gene expression in eukaryotic cells.
Transcription factors are proteins. Genes that encode proteins may undergo mutation. Describe how different kinds of gene mutation can lead to changes in the protein that is produced.
BLIMP-1 is a transcription factor essential for the formation of plasma cells and memory B-cells in the process shown in Fig. 3.1. BLIMP-1 lowers the synthesis of c-Myc in B-lymphocytes. c-Myc is a protein required for the mitotic cell cycle to proceed. Suggest and explain how a mutation in the gene coding for BLIMP-1 can stop the formation of plasma cells and memory B-cells.
Describe how a microarray is used to investigate gene expression.
BCL6 is another transcription factor in B-lymphocytes. The effect of BCL6 on gene expression was compared in two samples of B-lymphocytes. Sample 1 contained B-lymphocytes that were producing BCL6. Sample 2 contained B-lymphocytes that were not producing BCL6. Suggest why a microarray is suitable for identifying the function of the transcription factor BCL6 in these two samples.