文档介绍：W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. 1. The characteristics of microtubules 2. Microtubules during the cell cycle 3. The role of microtubules anelle positioning Lecture 7 The microtubule cytoskeleton 1 W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. Microtubules ? heterodimer (?-tubulin and ?-tubulin ) ? Protofilament ? 13 polar protofilaments /microtubule ? GTP ( ?-tubulin ) is hydrolyzed during assembly ? GTP ( ?-subunit) is never hydrolyzed 2 The GTP cap W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. 3 There is a delay between addition of subunits and GTP hydrolysis on ?-tubulin W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. 4 W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. 5 Microtubules undergo dynamic instability Growing and shrinking microtubules W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. 6 W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. Protein level ? generate DNA fusion construct DNA sequence of GFP fused to DNA sequence of the gene of interest (on N or C-terminus) ? Transfect construct into cells ? Analyze effect by microscopy Advantage : ? antibody staining is not necessary, ? GFP fluoresces by itself (when excited by correct light wave length) ? live imaging! Disadvantage : ? GFP is big ? may interfere with protein function and affect binding partners Tagging ?-tubulin with Green Fluorescent Protein ( GFP ) tubulin GFP DNA level 7 MT dynamics are controlled by MT-binding proteins W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. 8 W2011 - D103 Cell Biology – lecture 7 ? Suetterlin and MacGregor - all rights reserved. The centrosome is the major m icro t ubule o rganizing c ent