Gene Regulation Written Response Flashcards
One of the hallmarks of cancer is the fact that certain genes are expressed when they shouldn’t be while others are shut down when they are needed. Within this unit we have looked at ways that genes are expressed. What methods of eukaryotic expression could be playing a role in this and how?
Epigenetics - Methylations and acetylations tagged to genes that they shouldn’t be can turn on genes that aren’t needed and turn off genes that are.
Transcription Factors - If genes for transcription factors are mutated, or if an enhancer sequence is mutated, this can affect the interaction between activators and enhancers and can turn on genes that aren’t needed or shut off genes that are.
Titin is the longest protein in the human body and is encoded by one gene. Two forms of Titin are encoded by this gene depending on a person’s age. A longer, springier form is found in children, and a shorter, more rigid form is found in adults. What type of regulation accounts for this difference and how?
Alternative Splicing - Over time, the body splices the titin gene differently and removes certain exons from the mature mRNA strand. This makes the protein shorter and more rigid.
Many eukaryotic cell cycle processes involve the protein known as p53. This protein is activated at different times during a cell’s life cycle and is involved with many processes such as DNA Repair, Cell Cycle Arrest, and Apoptosis (programmed cell death). All 3 of these processes are part of the main function of Cell Cycle Control. What do you think p53 is and why?
p53 is a transcription factor. Since it is activated and involved with multiple functions at the same time, it is likely to be a transcription factor.
Inside the adrenal gland, amino acids are converted by other enzymes into the chemical adrenaline, which is known for its action in the “fight or flight” response. Although the code for these enzymes is found in every cell type of the body, only the cells of the adrenal medulla produce it. Using the information learned in this unit, describe one method that can account for this difference in expression.
Epigenetics -The adrenaline gene may be heavily methylated in other cells, but acetylated in the adrenal gland. This would explain why it’s on in the adrenal gland and off in all others.
Transcription Factors - It is possible that although every cell has the gene, only the adrenal gland cells have the transcription factor (activator) to turn the gene on.
Just because you put a gene into an organism does not mean they will use it. This is seen heavily in bacteria. Diabetic insulin is now primarily produced by bacteria given the gene for insulin as well as other regulatory sequences for the gene. Describe how the bacteria have needed to be manipulated in order to activate this gene and produce human insulin.
Manipulated Operon - The promotor, operator, and repressor gene of and operon can be genetically engineered to control insulin transcription. When exposed to the inducer for the repressor protein, the protein will fall off of the DNA and activate the Insulin Gene.
