Comparison of male chimeric mice generated from microinjection of JM8.N4 embryonic stem cells into C57BL/6J and C57BL/6NTac blastocysts

Abstract

To identify ways to improve the efficiency of generating chimeric mice via microinjection of blastocysts with ES cells, we compared production and performance of ES-cell derived chimeric mice using blastocysts from two closely related and commonly used sub-strains of C57BL/6. Chimeras were produced by injection of the same JM8.N4 (C57BL/6NTac) derived ES cell line into blastocysts of mixed sex from either C57BL/6J (B6J) or C57BL/6NTac (B6NTac) mice. Similar efficiency of production and sex-conversion of chimeric animals was observed with each strain of blastocyst. However, B6J chimeric males had fewer developmental abnormalities involving urogenital and reproductive tissues (1/12, 8%) compared with B6NTac chimeric males (7/9, 78%). The low sample size did not permit determination of statistical significance for many parameters. However, in each category analyzed the B6J-derived chimeric males performed as well, or better, than their B6NTac counterparts. Twelve of 14 (86%) B6J male chimeras were fertile compared with 6 of 11 (55%) B6NTac male chimeras. Ten of 12 (83%) B6J chimeric males sired more than 1 litter compared with only 3 of 6 (50%) B6NTac chimeras. B6J male chimeras produced more litters per productive mating (3.42 ± 1.73, n=12) compared to B6NTac chimeras (2.17 ± 1.33, n=6). Finally, a greater ratio of germline transmitting chimeric males was obtained using B6J blastocysts (9/14; 64%) compared with chimeras produced using B6NTac blastocysts (4/11; 36%). Use of B6J host blastocysts for microinjection of ES cells may offer improvements over blastocysts from B6NTac and possibly other sub-strains of C57BL/6 mice.

Comparison of BALB/c and B6-albino mouse strain blastocysts as hosts for the injection of C57BL6/N-derived C2 embryonic stem cells

“…It is not clearly understood why different combinations of ES cell and host embryo strains vary in their ability to produce germline-transmitting chimeras, but the consensus is that some host strains or substrains seem to have competitive advantage over the injected ES cell strain in colonizing the germline (Ledermann and Burki 1991;Papaioannou and Johnson 2000;Fielder et al 2012). For blastocyst injection of B6 ES cells, B6-albino host embryos were shown to be superior over FVB/NJ strain by Schuster-Gossler et al (2001) and BALB/c-derived host embryos superior over 129/Sv and Swiss Webster strains (Ledermann and Burki 1991;Auerbach et al 2000).…”

Mitochondrial DNA Genetics and the Heteroplasmy Conundrum in Evolution and Disease

“…The degree of enrichment for the NZB mtDNA in liver and kidney and against NZB mtDNA in the germline could then be influenced by mouse strain-specific genetic variation. One potentially relevant nDNA genetic variant is the loss of the nicotinamide nucleotide transhydrogenase gene (Nnt) on chromosome 13 in the Jackson Laboratory strain C57BL/6 J (Toye et al 2005;Huang et al 2006;Fielder et al 2012). NNT is a mitochondrial inner membrane protein, which uses the potential energy of the mitochondrial electrochemical gradient to transfer reducing equivalents from NADH to NADPH.…”

Host mitochondria influence gut microbiome diversity: A role for ROS

“…The mice were fed a 5LOD diet from PicoLab Laboratory and were maintained on a 13-hour/11-hour light-dark cycle. Seven mouse models were used for this study (Table 1); six were on C57BL/6J background (44)(45)(46): B6 mtDNA, ND6 m.13997 G>A (ND6 P25L ) (30), 129 mtDNA homoplasmic, NZB mtDNA homoplasmic, NZB/129 mtDNA heteroplasmic (35), and transgenic (Tg)-mCAT (31). The last strain was C57BL/6EiJ.…”