Similarly, in mouse embryonic fibroblasts (129Sv-C57BL/6 background), MAE was inferred using ChIP-Seq (Mikkelsen et al. 2007) and ENCODE RNA abundance data, then compared with allele-specific analysis of RNA-Seq in two independent clones from 129S1/Sv × CAST/EiJ F1 SV40-immortalized fibroblasts, Fib.1 and Fib.2 (Table S1).
The Drosophila simulans STCP lines were produced by Zabalou et al. [38] who transferred Wolbachia wYak, wTei, wSan strains into the same host background using embryonic cytoplasmic injections.
Similar to the situation in the human disease, expression of the human SMN2 gene in the mouse Smn null background rescues embryonic lethality and results in mice with SMA [15], [16].
Whilst it was not possible to assess testis function on B6 due to non-viability, marker analysis of XY embryonic gonads on this background indicates that primary sex determination occurs as normal, with all major testicular lineages present and no evidence of inappropriate, widespread ovarian marker expression.
PPARβ/δ knockout animals display high embryonic mortality on inbred background [49].
We generated Cx30T5M mutant mice via homologous recombination in murine HM1 embryonic stem cells (genetic background 129P2).
This mouse model was generated on C57B6/J background using embryonic stem cell-mediated strategy, and HMGA2 expression was controlled by the CMV promoter.
The JJ1549 strain has a background of embryonic lethality of only 6% more than the wild-type (see Results section) and thus it is a good strain to use in synthetic genetic screening for embryonic lethality.
In our own analyses, we discovered that the gasping mutants (Ermakov et al., 2009) show differing timing of embryonic death on different background strains, with earlier death on B6J than C3H (D.P.N., Alexander Ermakov and Paraskevi Goggolidou, unpublished data).
An early Cul-4a KO study using the Cre/loxP strategy to ablate exon 1 of the Cul-4a gene showed that Cul-4a deletion in Cul-4b wild-type background causes embryonic lethality at E7.5, suggesting that Cul-4a is essential to early embryogenesis, and that Cul-4a and Cul-4b are functionally non-redundant.
