STRAIN DIFFERENCE IN ESTABLISHMENT OF MOUSE EMBRYONIC STEM (ES) CELL-LINES

For utilization of the mouse embryonic stem (ES) cells for various pur poses, it is desirable that the cell lines are established from variou s sources such as inbred and mutant mouse strains. So far, however, mo st ES cell lines used in genetic manipulation have been derived from t he 129/Sv strain. We have established ES cell lines from blastocysts o f the C57BL/6 strain at high efficiency by use of a fibroblast cell li ne SL10 as feeder cells, and supplementing the culture medium with 5,0 00 unit/ml LIF. Using such culture conditions, we have also establishe d a number of ES cell lines from the BALB/c, BXSB/MpJ-Yaa and MRL/Mp-I pr/Ipr mouse strains. Procedure for establishment of ES cell lines had to be modified among the mouse strains, indicating the strain differe nce. For example, only a few stem cell colonies appeared from the BALB /c blastocysts. Stem cells of the BXSB strain were very sensitive to t he trypsinization in subculturing. Most of these cell lines had normal karyotype and produced chimeric mice. Several C57BL/6 cell lines cont ributed to the germ-line. These results indicate that ES cell lines ca n be established from various mouse strains, but their characteristics are different among strains.