A membrane reticulum, the centriculum, affects centrosome size and function in Caenorhabditis elegans.

Centrosomes are cellular structures that nucleate microtubules. At their core is a pair of centrioles that recruit pericentriolar material (PCM). Although centrosomes are considered membraneless organelles, in many cell types, including human cells, centrosomes are surrounded by endoplasmic reticulum (ER)-derived membranes of unknown structure and function.

An RNAi screen for genes that affect nuclear morphology in Caenorhabditis elegans reveals the involvement of unexpected processes.

Aberration in nuclear morphology is one of the hallmarks of cellular transformation. However, the processes that, when mis-regulated, result aberrant nuclear morphology are poorly understood. In this study, we carried out a systematic, high-throughput RNAi screen for genes that affect nuclear morphology in Caenorhabditis elegans embryos.

Cell biology: How does the nucleus get its membrane?

Nuclear shape and size depend on nuclear membrane availability through an unknown process. A new study of asymmetric cell division reveals that nuclear membrane is derived from the endoplasmic reticulum and that limiting nuclear membrane expansion can affect cell fate.

A Workflow for High-pressure Freezing and Freeze Substitution of the Embryo for Ultrastructural Analysis by Conventional and Volume Electron Microscopy.

The free-living nematode is a popular model system for studying developmental biology. Here we describe a detailed protocol to high-pressure freeze the embryo (either after dissection, or within the intact worm) followed by quick freeze substitution. Processed samples are suitable for ultrastructural analysis by conventional electron microscopy (EM) or newer volume EM (vEM) approaches such as Focused Ion Beam Scanning Electron Microscopy (FIB-SEM).

Cryo-fluorescence microscopy of high-pressure frozen C. elegans enables correlative FIB-SEM imaging of targeted embryonic stages in the intact worm.

Rapidly changing features in an intact biological sample are challenging to efficiently trap and image by conventional electron microscopy (EM). For example, the model organism C. elegans is widely used to study embryonic development and differentiation, yet the fast kinetics of cell division makes the targeting of specific developmental stages for ultrastructural study difficult.