Induction of bcl-xL mRNA and protein by GATA-1 in G1E-ER2 cells. G1E-ER2 and parental G1E cells were treated with estradiol (E2) or tamoxifen (Tamox) and sampled for bcl-x mRNA and protein at the indicated times. (A) Northern blot analysis using a bcl-xL cDNA probe. Each lane contains 20 μg of total RNA. (B) Expression of splice variants bcl-xL, bcl-xs, and bcl-xβ in maturing G1E-ER2 cells. The top panel shows a schematic of the various bcl-x mRNAs examined and the primers used for detection by RT-PCR. The bottom panels show the RT-PCR reactions for bcl-xL and bcl-xs (left) and bcl-xβ (right). The positive controls are bcl-xL cDNA plasmid (C) and mouse thymus cDNA (T). (C) bcl-x protein expression in G1E-ER2 cells. For Western analysis (left panel), 50 μg of protein from whole-cell lysates was fractionated on a 14% SDS polyacrylamide gel. 35S methionine-labeled in vitro transcribed/translated (TNT) bcl-xL and bcl-xβ isoforms were fractionated in adjacent lanes (right panel).
