The transcription of a gene can be decreased by the following:

A. Increase in histone deacetylases: Histone deacetylases (HDACs) are enzymes that remove acetyl groups from an ε-N-acetyl lysine amino acid on a histone, allowing the histones to wrap the DNA more tightly. This decrease in space between the DNA and histones makes it harder for transcription factors and RNA polymerase to access the DNA, thus decreasing transcription.

B. Increase in histone acetyltransferases: This would actually increase transcription, not decrease it. Histone acetyltransferases (HATs) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl CoA to form ε-N-acetyl lysine. This acetylation of the histones loosens the DNA around them, making it easier for transcription factors and RNA polymerase to access the DNA and increase transcription.

C. Decrease in DNA methyltransferases: This would also increase transcription, not decrease it. DNA methyltransferases are enzymes that transfer a methyl group to DNA. Methylation of DNA can repress gene transcription by preventing the binding of transcription factors and RNA polymerase to the DNA.

D. Decrease in CpG methylation of promoter: This would increase transcription, not decrease it. Methylation of CpG sites in a gene promoter region can prevent the binding of transcription factors, thus repressing gene transcription. If there is a decrease in CpG methylation of the promoter, then transcription factors can bind more easily, increasing transcription.

So, the correct answer is A. Increase in histone deacetylases.

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The transcription of a gene can be decreased by the following:

A. Increase in histone deacetylases: Histone deacetylases (HDACs) are enzymes that remove acetyl groups from an ε-N-acetyl lysine amino acid on a histone, allowing the histones to wrap the DNA more tightly. This decrease in space between the DNA and histones makes it harder for transcription factors and RNA polymerase to access the DNA, thus decreasing transcription.

B. Increase in histone acetyltransferases: This would actually increase transcription, not decrease it. Histone acetyltransferases (HATs) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl CoA to form ε-N-acetyl lysine. This acetylation of the histones loosens the DNA around them, making it easier for transcription factors and RNA polymerase to access the DNA and increase transcription.

C. Decrease in DNA methyltransferases: This would also increase transcription, not decrease it. DNA methyltransferases are enzymes that transfer a methyl group to DNA. Methylation of DNA can repress gene transcription by preventing the binding of transcription factors and RNA polymerase to the DNA.

D. Decrease in CpG methylation of promoter: This would increase transcription, not decrease it. Methylation of CpG sites in a gene promoter region can prevent the binding of transcription factors, thus repressing gene transcription. If there is a decrease in CpG methylation of the promoter, then transcription factors can bind more easily, increasing transcription.

So, the correct answer is A. Increase in histone deacetylases.

Knowee AI · Accepted Answer

The transcription of a gene can be decreased by the following:

A. Increase in histone deacetylases: Histone deacetylases (HDACs) are enzymes that remove acetyl groups from an ε-N-acetyl lysine amino acid on a histone, allowing the histones to wrap the DNA more tightly. This decrease in space between the DNA and histones makes it harder for transcription factors and RNA polymerase to access the DNA, thus decreasing transcription.

B. Increase in histone acetyltransferases: This would actually increase transcription, not decrease it. Histone acetyltransferases (HATs) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl CoA to form ε-N-acetyl lysine. This acetylation of the histones loosens the DNA around them, making it easier for transcription factors and RNA polymerase to access the DNA and increase transcription.

C. Decrease in DNA methyltransferases: This would also increase transcription, not decrease it. DNA methyltransferases are enzymes that transfer a methyl group to DNA. Methylation of DNA can repress gene transcription by preventing the binding of transcription factors and RNA polymerase to the DNA.

D. Decrease in CpG methylation of promoter: This would increase transcription, not decrease it. Methylation of CpG sites in a gene promoter region can prevent the binding of transcription factors, thus repressing gene transcription. If there is a decrease in CpG methylation of the promoter, then transcription factors can bind more easily, increasing transcription.

So, the correct answer is A. Increase in histone deacetylases.

Which of the following will lead to a decrease in transcription of a gene?A. Increase in histone deacetylases.B. Increase in histone acetyltransferases.C. Decrease in DNA methyltransferases.D. Decrease in CpG methylation of promoter

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