The key step is the lysis which solubilizes centrosomes away from nuclei by very low ionic strength lysis after treatment of cells with nocodazole and cytochalasin B. The released centrosomes are then centrifuged onto a Ficoll cushion (to avoid pelleting) and the interface between the lysate and the Ficoll is collected and the centrosomes are concentrated on a sucrose gradient. Fractions are assayed by spindown and double IF with 5051 serum and anti-tubulin and the pooled fractions are frozen... - [Read CHO Centrosome Prep Protocol]
This protocol describes a rapid PCR-based method for identifying targeted ES cell colonies prior to picking. It is based on DNA analysis of a small part of colonies pooled directly from selection plates. Only positive colonies are expanded. - [Read Genotyping Embryonic Stem (ES) Cell Colonies Prior to Picking Protocol]