Question

Dioxin, produced as a by-product of various industrial chemical processes, is suspected of contributing to the development of cancer and birth defects in animals and humans. It apparently acts by entering cells by simple diffusion and binding to proteins in the cytoplasm, then altering the pattern of gene expression. Which of the following are likely to be the cytoplasmic proteins to which dioxin binds?a. nucleosomes
b. DNA polymerases
c. enhancers
d. transcription factors
e. growth factor receptors

Answer 1

Answer:

d. transcription factors

Explanation:

Transcription factors are the proteins present in cells that are involved in the regulation of gene expression. The transcription factors may increase or decrease the expression of a gene. Therefore, a transcription factor may serve as an activator or repressor for a gene. These proteins bind to a regulatory sequence present near or within a gene, interact with RNA polymerase or other transcription factors and thereby, affect the transcription initiation.

Since binding of dioxin to certain proteins alter the pattern of gene expression in the cells, these proteins are the transcription factors. For instance, dioxin may bind to a transcription factor and up-regulate the expression of genes which in turn regulate the cell division.