A screen has identified a mutant cell that is unable to migrate along the basal lamina. Sequence analysis reveals the presence of two mutations in the transmembrane domain of integrin alpha 6, that normally localizes to the plasma membrane, and which plays a critical role in cell adhesion. The mutations are as follows: Leu --> Asp and Trp --> Lys. Which of the following statements best describes a reason for why the mutant cell does not migrate in a fibronectin-coated dish? The cell does not migrate because a. the cell cannot form desmosomes b. the cell cannot form an adhesion belt c. the cell cannot form the branched actin cytoskelton at the leading edge d. the cell cannot adhere to the fibronectin that has been used to coat the dish e. The cell is unable to link its actin to the ECM via cadherins

The correct option is D (the cell cannot adhere to the fibronectin that has been used to coat the dish).

Explanation:

Mutation is an alteration in DNA sequences which occurs due to insertion, deletion or base substitution. This in turn leads to different malfunctions of the cell. Sequence analyses are methods that are used to determine the amino acid sequence of parts of a protein. For example, when a DNA is subjected to sequence analysis,it helps to identify differences and variations such as mutation.

The mutant cell identified in the screen revealed the presence of two mutations in the transmembrane that plays a critical role in cell adhesion. The cell does not migrate because the cell cannot adhere to the fibronectin that has been used to coat the dish, thus, the adhesion properties is lost due to mutation in the transmembrane. I hope this helps, thanks.