Fig. 4Immunoblot comparison of hGR translatedin vitro within vivo hGR from cell extracts,a, The vectors constructed forin vitro transcription of the hGR cDNA sequence. The completeα (pGR107) andβ (pGR108) coding sequences were placed under the transcriptional control of the SP6 promoter in pGEMl. Vector sequences, noncoding cDNA sequences and coding sequences are indicated by thin lines, thick bars and boxed regions, respectively. The poly(A) tract of ~60 nucleotides is indicated by A.,. Divergent coding sequences are indicated by striped and stippled regions,b, Western blot analysis ofin vitro translation products and cell extracts. Unlabelled translation products synthesized in a rabbit reticulocyte lysate system with no added RNA (lane 1) or with RNA synthesized from pGR108 (β, lane 2) or pGR107 (α, lane 3) were fractionated on a 7.5% SDS-polyacrylamide gel. Additional lanes are: cytoplasmic extracts from IM-9 (lane 4), IM-9 treated with 1 μM triamcinolone acetonide (lane 5), HeLa (lane 6), ADR6.M1890.AD1 mouse lymphoma (lane 7), S49 mouse lymphoma (lane 8) and EL4 lymphoma (lane 9). Proteins were transferred to nitrocellulose and probed with anti-hGR antibody, followed by125I-labelIedStaphylococcus aureus protein A as described previously.Methods. To construct an expression vector containing the entireα coding sequence shown in Fig. 2, the 3’ coding sequence of OB7 was fused to OB10 5’ coding information. OB7 was partially digested withEcoRI, completely digested withX baI, and the 1.2-kbp fragment was gel-purified and ligated withEcoRI/baI-digested OB10 to produce the intermediate pOB107. The entire pOBl07 cDNA sequence including the 5’ poly(G) tract (11 nucleotides, nt) and 3’ poly(A) tract (~ 6 0 nt) was excised by partialPst I/completeBam HI digestion. The resultant 3.5-kb fragment was gel-purified and inserted between thePstI and Bam HI sites of pGEM l (Promega Biotec) to yield pGR107. Plasmid GR108 was directly constructed from pOB10 by partialPstI/com pleteBam HI digestion and insertion of the resulting cDNA insert into the corresponding sites of pGEMl. Capped SP6 transcripts were synthesized fromPvuII-linearized pGR107 and pGR108, as described by Kjieg and Melton, with simultaneous capping effected by reduction of the GTP concentration from 400 to 100 μM and addition of m7GppG (Pharmacia) to 500 μM. Transcripts were purified by P60 chromatography and translated with micrococcal nuclease-treated rabbit reticulocyte lysate (Promega Biotec) in conditions suggested by the manufacturer. Preparation of IM-9 cytosol from steroid-treated cells was as described previously. Size markers are phosphorylase B (97K), bovine serum albumin (66K.) and ovalbumin (45K).