Question

An accepted model for mitotic spindle assembly involves the so-called “search and capture” mechanism whereby microtubules are nucleated from the two centrosomes at the spindle poles with their plus ends extending toward the spindle midzone. In this model, the microtubule plus ends in the spindle midzone capture chromosomes by binding to their kinetochores. Once all chromosomes are bioriented they align at the metaphase plate in preparation for anaphase

Describe the phenotype caused by addition of anti-Kinesin 5 antibodies to the extract. What is the best explanation for this phenotype?

Describe the phenotype caused by addition of anti-Dynein antibodies to the extract. What is the best explanation for this phenotype?  

Answer 1

Addition of anti-kinesin antibodies to the cell extract bonds to kinesin proteins of the cell in anaphase to block spindle movement followed by inhibiting chromosomal separation. The cannot progress through cell division, so cell may become polyploid. In normal cells, Kinesin 5 family proteins otherwise act within spindle to slide microtubules apart from each other.

Antidynein antibody may inhibit the proper spindle positioning in the site of cytokinesis, so the chromosomal segregation is impacted. The cells become aneuploid or polyploid. In normal cells, the dynein protein plays a key role in spindle positioning and pulling of astral microtubules etc.