(A) Western blot of total protein lysates from mouse embryonic fibroblasts (MEFs), probed with anti-CITED2 antibody. CITED2 and CITED2-MRG1 are indicated, as is a non-specific band (N.S.) that migrates at 25 kDa. (B) RT-PCR showing RNA products expressed by embryos of various genotypes. PCR primers were designed to differentiate between the endogenous mouse Cited2 transcript and the Cited2 MRG1 transcript by their size difference. Wild type mouse Cited2, containing the SRJ domain produces the larger 725 bp band. (C) Southern blots of Cited2 T166N allele. Top, Southern blot of EcoRI digested genomic DNA probed with a 5′-probe. Middle, Southern blot of BglII digested genomic DNA, probed with a 3′-probe. Probe positions are indicated in Fig. 3. Bottom, Southern blot of SpeI digested genomic DNA hybridized with an internal (Neomycin) probe, to confirm single copy integration. (D) Southern blots of Cited2 MRG1 and Cited2 HUM alleles. Top, Southern blot of EcoRI/SacII digested genomic DNA, probed with a 5′-probe. Middle, Southern blot of BglII digested genomic DNA, probed with a 3′-probe. The position of the probes is indicated in Fig. 3. Bottom, Southern blot of EcoRI digested genomic DNA hybridized with an internal (Puromycin) probe to confirm single copy integration.