Figure 4.

Targeted disruption of the mouse ESG1 gene. A) Targeting strategy. Homologous regions are indicated by thick lines. Recognition sites of PstI (P) and SpeI (S), which were used for Southern blot analyses, are shown. The gene encoding diphtheria toxin A (DTA) was inserted at the 3' end of the targeting vectors to facilitate negative selection. B) Southern blot analyses confirming homologous recombination. WT, wild-type ES cells; β, β-geo +/- ES cells; H, HygR +/- ES cells; -/-, ESG1-null ES cells. Numbers indicate clone numbers. C) Northern blot (upper) and western blot (lower) analyses of wild-type ES cells (WT), ESG1-null ES cells (-/-, three clones) and heterozygous ES cells (+/-). Northern blot was performed as previously described [20]. To confirm the loading of equal amounts of RNA, ethidium bromide staining of ribosomal RNA is also shown (middle).