Normally, the FgfR3 protein (a receptor tyrosine kinase) is activated by a fibroblast growth factor and signals the chondrocytes to stop dividing and begin differentiating into cartilage. This signal is mediated by the Stat protein, which is phosphorylated by activated FgfR3 and then translocated into the nucleus. Inside the nucleus, Stat activates the genes encoding a cell cycle inhibitor, the p21 protein. The mutation in FgfR3 causes the lethal condition thanatophoric dysplasia. This condition may be achieved by:

A. Mutations in the extracellular domain of the FgfR3 protein

B. Mutations in the tyrosine kinase intracellular domain of the FgfR3 protein

C. Mutations in the transmembrane domain of the FgfR3 protein

Which of the following is correct?

#Question id: 4530

#Unit 3. Fundamental Processes

A protein complex engaged in the pairing of homologous chromosomes during cell division has also been implicated in stabilizing certain enhancer–promoter loops.

#Question id: 4531

#Unit 3. Fundamental Processes

Specific elements called insulators control the actions of activators. When placed between an enhancer and a promoter,

#Question id: 4532

#Unit 3. Fundamental Processes

Locus control region, or LCR,

#Question id: 4533

#Unit 3. Fundamental Processes

When multiple activators work together, they often do so synergistically. That is, the effect of

#Question id: 4534

#Unit 3. Fundamental Processes

The yeast Saccharomyces cerevisiae divides by budding: instead of dividing to produce two identical daughter cells, the so-called mother cell buds to produce a daughter cell, The HO gene is expressed only in mother cells and only at a certain point in the cell cycle,

#Question id: 4535

#Unit 3. Fundamental Processes

The activators bind—and the enhanceosome forms—in a highly cooperative manner, ensuring that all three activators must be present. The following are three ways the regulators might be binding cooperatively:

I- Through direct protein–protein interactions between them

II- By changes in the DNA caused by binding of one protein helping binding of another;

III- By the fact that the activators all interact simultaneously with the coactivator.