Search

Fast-acting temperature-sensitive (ts) mutations are powerful conditional tools for studying transient cellular processes such as cytokinesis. Fast-acting ts cytokinesis-defective mutants are functional at the permissive temperature; yet show a fully penetrant loss-of-function cytokinesis failure phenotype when upshifted to the restrictive temperature. Fast-acting ts mutations thus allow functional tunability and rapid and reversible protein inactivation by simply shifting the temperature at precise times throughout cell division. In this chapter, we describe several techniques and discuss various approaches for harnessing the power of fast-acting ts mutants to study cytokinesis in Caenorhabditis elegans using both simple passive heat transfer and more advanced fluidic-based thermal control systems. We also provide detailed protocols for standard dissection, mounting, and imaging of early worm embryos.

Cytokinesis is the physical division of one cell into two daughter cells that occurs at the end of the cell cycle.1 Cytokinesis is thought to be fundamentally similar in all metazoan divisions-that...

In asymmetrically dividing C. elegans embryos, the core cortical PAR proteins are required to retain septin and anillin at the anterior cortex away from the contractile ring and to promote normal F-actin levels at the contractile ring and successful cytokinesis., Cytokinesis, the physical division of one cell into two, is thought to be fundamentally similar in most animal cell divisions and driven by the constriction of a contractile ring positioned and controlled solely by the mitotic spindle. During asymmetric cell divisions, the core polarity machinery (partitioning defective [PAR] proteins) controls the unequal inheritance of key cell fate determinants. Here, we show that in asymmetrically dividing Caenorhabditis elegans embryos, the cortical PAR proteins (including the small guanosine triphosphatase CDC-42) have an active role in regulating recruitment of a critical component of the contractile ring, filamentous actin (F-actin). We found that the cortical PAR proteins are required for the retention of anillin and septin in the anterior pole, which are cytokinesis proteins that our genetic data suggest act as inhibitors of F-actin at the contractile ring. Collectively, our results suggest that the cortical PAR proteins coordinate the establishment of cell polarity with the physical process of cytokinesis during asymmetric cell division to ensure the fidelity of daughter cell formation.

Apple’s OS X has a steady growth within the United States. This also means digital forensics laboratories will likely see more OS X products. This chapter looks at Mac OS X 10.11 El Capitan. The chapter begins at the top level or root directory, and it works down the file system. This chapter highlight areas of forensic interest. However, it also takes a basic look at the file system as a whole. This chapter gives the analyst a foundation in OS X. There is also a quick guide at the back of the chapter providing paths to key forensic information.

King’s work focuses on the intimate biomechanical link between the nucleus and the cytoskeleton.

Kraft’s work focuses on the mechanisms that regulate autophagy in response to nutrient availability.

Brangwynne’s work centers on the phase transitions that underlie various aspects of cell biology.

Cheney’s work focuses on the molecular basis of cell movement.

Forman-Kay provides key structural insights into the biological functions of intrinsically disordered proteins.