Passage of Embryonic Stem (ES) Cells

Preparation of DNA from Embryonic Stem Cells or Other Cultured Cells

Characterization of embryonic stem (ES) cell-mediated genome alterations, including random insertional transgenesis, gene trapping, gene targeting, and site-specific recombinase-mediated changes, is performed mostly at the ES cell level, before the introduction of these alterations into a mouse. A detailed characterization requires a larger amount of DNA than is required for the initial detection of the candidates for the desired alteration. This protocol describes the preparation of DNA from a 10-cm tissue culture plate. The cells are trypsinized and lysed, and DNA is recovered from the lysate by organic extraction followed by ethanol precipitation.

Testing Serum Batches for Mouse Embryonic Stem Cell Culture

The variability in embryonic stem (ES) cell culture is due primarily to serum. Serum is typically produced in large batches from many animals. However, samples may differ depending on the age and diet of the animals, the country of origin, and other factors creating lot-to-lot variations. Some vendors test FBS lots for compatibility with ES cell culture. Many laboratories prefer to test serum batches themselves to identify the lot giving optimal growth. In this protocol, small quantities of specific serum batches are obtained from different suppliers and tested for their ability to support ES cells in an undifferentiated state. A complete test includes the serum batches' influence on plating efficiency, cell morphology, toxicity, and, if possible, their ability to support generation of chimeras.

Differentiating Mouse Embryonic Stem Cells into Embryoid Bodies by Hanging-Drop Cultures

Embryonic stem (ES) cells can develop into many types of differentiated tissues if they are placed into a differentiating environment. This can occur in vivo when the ES cells are injected into or aggregated with an embryo, or in vitro if their culture conditions are modified to induce differentiation. There are an increasing number of differentiating culture conditions that can bias the differentiation of ES cells into desired cell types. Determining the mechanisms that control ES cell differentiation into therapeutically important cell types is a quickly growing area of research. Knowledge gained from these studies may eventually lead to the use of stem cells to repair specific damaged tissues. Many times ES cell differentiation proceeds through an intermediate stage called the embryoid body (EB). EBs are round structures composed of ES cells that have undergone some of the initial stages of differentiation. EBs can then be manipulated further to generate more specific cell types. This protocol describes a method to differentiate ES cells into EBs. It produces EBs of comparable size. This aspect is important because the differentiation processes taking place inside an EB are influenced by its size.

Thawing embryonic stem (ES) cells from a 96-well plate

INTRODUCTION

The most widely used method to alter the genome of embryonic stem (ES) cells is to introduce a specifically designed DNA fragment using electroporation. The DNA will then integrate into the genome of ES cells. Colonies of cells containing the exogenous DNA are then picked, expanded, replica-plated, frozen in 96-well plates, and used as a source for genomic DNA preparation for genotyping. After ES candidate clones are identified by genomic Southern blot or polymerase chain reaction (PCR), the method of rescue of the cells from the frozen 96-well plates is very important. This protocol describes a method for thawing such cells.