The v6.5 mouse embryonic stem cell line was developed in the laboratory of Dr. Rudolph Jaenisch of the Whitehead Institute. The cell line was established from cells derived from the inner cell mass (ICM) of a 3.5 day old mouse embryo from a C57BL/6 X 129/sv cross and has been used successfully in producing germline transmitting chimeras. The v6.5 mouse ES cell lines is the parent strain from which the DGCR8 -/- knockout cell line (NBA1-19349) is derived.