Rescue of established ES cell lines
RESGRO Culture Medium has the capacity to rescue established ES cell lines that have started drifting, and either generate low percentage chimeras or have lost germline transmission capability. Differentiation, which is present in the ES cells but not visible with traditional medium, will become recognizable when using RESGRO Culture Medium. After 2 passages, a clear difference is seen between differentiated and undifferentiated ES cells, at which time undifferentiated cells can be selected for by sub-cloning.
Murine ES cell derivation
The efficiency of ES cell derivation is greatly strain dependent. To date, very few murine ES cell lines are available from inbred strains other than 129 strains, and those derived have generally been obtained with low success rates. Furthermore, ES cells derived from other strains than 129 are in general more difficult to propagate in vitro. Especially at high passage number and after genetic manipulation, these cell lines generate chimeras less efficiently and contribute less frequently to the germline.
RESGRO Culture Medium enables the efficient derivation and maintenance of ES cell lines from several inbred mouse strains, including certain strains that were previously considered to be non-permissive for ES cell derivation. A recent study demonstrated that RESGRO™ allowed the derivation of ES cell lines from inbred strains other than 129 (including FVB, a strain previously considered to be non-permissive for ES cell derivation and C57Bl/6N, BALB/c, 129/SvEv and DBA/2N mouse strains)1.
Culture of ES cells without a fibroblast feeder layer
RESGRO Culture Medium allows for the culture of ES cells on bare (gelatinized) culture dishes. Even in the absence of a fibroblast feeder layer ES cells maintain their undifferentiated character and their germline transmission capability for at least 5 passages, when cultured with RESGRO Culture Medium. After trypsinization pure ES cell suspensions without fibroblast cells can be obtained. Fibroblast cells will no longer interfere during blastocyst injections, diploid aggregations, tetraploid aggregations and electroporations.