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E.5.a.
E.5.b.

 

 

   Otherwise identical cultures of hippocampal neurons expressing the chimeric gene APP-YFP were treated with either the antisense or the sense nucleotides for kinesin heavy chain. The two cultures were examined by fluorescence microscopy, and the movement of tubular vesicles containing APP-YFP was traced, as illustrated in the figures below: on the left, a culture treated with sense nucleotides; one treated with antisense nucleotides shown on the right. Clicking on each figure will bring up the corresponding movie.

Each movie frame image is about 40 mm wide: the axon treated with sense nucleotides in the left-hand movie is approximately 57 mm long, while the one on the left is about 44 mm long. The "sense movie" lasts 2 sec and contains 34 frames, which were recorded at a rate of 0.77 frame per sec, while the "antisense movie" lasts 5.5 sec and contains 71 frames, which were recorded at a rate of 0.58 frames per sec. Thus, in both instances vesicle movements are speeded up about 22-fold. Watch each movie several times, run continuously and one frame at a time, and answer the accompanying questions.

[For more information about fast axonal transport, please consult the research article by Kaether, C. et al., 2000, Mol. Biol. Cell. 11:1213-1224. PMID10749925.]

Questions

A. Carefully describe the vesicular movements in both movies, qualitatively and quantitatively.

B. What are sense and antisense nucleotides?

C. What do these data indicate about the mechanism of vesicle movement in hippocampal axons?

 

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