Mutant mice can be generated to have different mutations in cytoskeletal proteins. These mice serve as model systems for human cytoskeletal diseases. Match each of the following mice strains afflicted with cytoskeleton mutant phenotypes with the protein whose activity has been disrupted.
1. Mouse mutant 1 has normal looking sperm with normal length tails but the sperm are nonmotile and do not move when visualized in the microscope.
2. Mouse mutant 2 develops abnormally tight muscles and upon closer investigation it is found that the mouse muscle is contracting more than normal.
3. Mouse mutant 3 shows extensive skin blistering and open sores that arise from even minor touching of the mouse skin.
4. Mouse mutant 4 slowly develops muscle weakness over time. The muscles appear normal but the neurons that signal the muscles show axonal degeneration at the nerve termini oflong axons.

a.kinesin
b.myosin
c.tubulin
d.dynein
e.tropomyosin
f.keratin