You have used a reporter gene system to investigate the contribution to gene expression of three cis-regulatory DNA sequences (A to C) from a key developmental gene. Reporter gene expression from constructs containing all three or only a subset of the regulatory sequences is summarized in the diagram below. According to these findings, indicate whether each of the following conclusions is (Y) or is not (N) acceptable. Your answer would be a four-letter string composed of letters Y and N only, e.g. NNNN.

( ) Region B is likely to normally bind an activator and turn the gene on.
( ) Region C is sufficient for activation of gene expression.
( ) Region A is necessary for activation of gene expression.
( ) Region C is necessary for activation of gene expression.

Question

You have used a reporter gene system to investigate the contribution to gene expression of three cis-regulatory DNA sequences (A to C) from a key developmental gene. Reporter gene expression from constructs containing all three or only a subset of the regulatory sequences is summarized in the diagram below. According to these findings, indicate whether each of the following conclusions is (Y) or is not (N) acceptable. Your answer would be a four-letter string composed of letters Y and N only, e.g. NNNN.
  
( )	Region B is likely to normally bind an activator and turn the gene on.
( )	Region C is sufficient for activation of gene expression.
( )	Region A is necessary for activation of gene expression.
( )	Region C is necessary for activation of gene expression.

Quizplus · Accepted Answer

Only region A appears to be necessary for activation of reporter gene expression, as eliminating either B or C (or both) does not shut down gene expression. In the absence of region B, expression is increased almost twofold, suggesting that this region is inhibitory. The presence of region C increases expression, but only when region A is also present.

You Have Used a Reporter Gene System to Investigate the Contribution