Final answer:
The expression of the cI gene, which is involved in the regulation of the lambda bacteriophage life cycle, is established and maintained through a complex regulatory mechanism. The cI gene encodes for a transcription factor that controls the expression of other genes within the bacteriophage genome. This regulation is crucial for maintaining the balance between different life cycle modes of the bacteriophage.
Step-by-step explanation:
Expression of the cI gene is established and maintained through a complex regulatory mechanism. The cI gene encodes for a transcription factor that controls the expression of other genes in a bacteriophage called lambda. The expression of cI is tightly regulated to ensure proper control of the bacteriophage life cycle. When lambda infects a bacterial cell, the cI gene is initially expressed, leading to the production of the cI transcription factor. This transcription factor then binds to specific DNA sequences called operator sites, which are located within the lambda genome. By binding to these operator sites, cI can either activate or repress the expression of various genes within the lambda genome. The exact mechanisms by which cI regulates gene expression can vary depending on the specific genes involved and the environmental conditions. However, in general, cI acts as a master regulator that can switch the lambda bacteriophage between different life cycle modes, such as the lytic cycle (where the bacteriophage replicates and ultimately lyses the bacterial cell) and the lysogenic cycle (where the bacteriophage integrates into the bacterial genome and remains dormant). Maintaining the proper expression of cI is crucial for maintaining the balance between these different life cycle modes and ensuring the survival of the bacteriophage.