I’m not sure I’m probably rlly wrong but I think the answer is E
Answer:
undergo irreversible repression
Explanation:
Cellular differentiation refers to the process by which one cell and/or cell population divides and differentiates into more specialized cells. During cell fate differentiation, epigenetic marks modify chromatin structure in order to hamper the accessibility of the transcriptional machinery and transcriptional factors to different genes, which are irreversibly repressed. These epigenetic marks include DNA methylation and histone modifications (e.g., histone acetylation, histone methylation, etc). For example, it has been shown that DNA methylation and histone H3 lysine 27 tri‐methylation (H3K27me3) are epigenetic repressive marks on genomic regions that play a major role in gene expression programs during cell fate differentiation.
You have to have both the pL promoter as well as a second system of the cI repressor which controls the pL promoter.
When the cI repressor is expressed it will bind onto the operator region of the pL promoter and prevent expression.
When the cI repressor is not expressed it can't bind to its operator and the pL promoter (which is very strong) can express whatever gene it is upstream of.
So you need to have both for transcriptional control. you don't need the rest of the phage!
