Expression of mRNA of transcription factors in the VE-cadherin⁺ 4-integrin⁻, VE-cadherin⁺ 4-integrin⁺, VE-cadherin⁻ 4-integrin⁻, and VE-cadherin⁻ 4-integrin⁺ cells induced in vitro from ES cell-derived FLK1⁺ cells. These fractions were all CD45⁻ TER119⁻. Different dilutions of cDNA prepared from sorted cells were subjected to PCR amplification specific for Gata1, Gata2, Tal1,Lmo2, Myb, and Gapd transcripts. PCR products were separated on 1% agarose gel stained with ethidium bromide. The result shown is a representative of two independent experiments.