You Have Performed a Chromosome Conformation Capture (3C) Experiment to Study

question 6

Short Answer

You have performed a chromosome conformation capture (3C) experiment to study chromatin looping at a mouse gene cluster that contains genes A, B, and C, as well as a regulatory region R. In this experiment, you performed in situ chemical cross-linking of chromatin, followed by cleavage of DNA in the nuclear extract with a restriction enzyme, intramolecular ligation, and cross-link removal. Finally, a polymerase chain reaction (PCR) was carried out using a forward primer that hybridizes to a region in the active B gene, and one of several reverse primers, each of which hybridizes to a different location in the locus. The amounts of the PCR products were quantified and normalized to represent the relative cross-linking efficiency in each analyzed sample. You have plotted the results in the graph below. The same experiment has been done on two tissue samples: fetal liver (represented by red lines) and fetal muscle (blue lines).
Interaction of the A, B, and C genes with the regulatory R region is known to enhance expression of these genes. Indicate true (T) and false (F) statements below based on the results. Your answer would be a four-letter string composed of letters T and F only, e.g. TTTF.

( ) The B gene would be predicted to have higher expression in the fetal liver compared to the fetal muscle tissue.
( ) Interaction between the R region and the B gene involves the A gene looping out.
( ) Interaction between the R region and the B gene involves the C gene looping out.
( ) In fetal muscle, the B gene definitely does not engage in looping interactions with any other elements in the cluster.

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Definitions:

Metabolic Pathway

A series of chemical reactions in which the product of one reaction becomes the substrate of the next reaction.

Enzyme

Biological molecules that act as catalysts, speeding up chemical reactions in the body without being consumed in the process.

Mutant Gene

A gene that has undergone mutation, altering its original function, which can have various effects on an organism's phenotype.

Uracil

(uracil) A nitrogenous pyrimidine base found in RNA.