Multiple glucocorticoid receptor transcripts in membrane glucocorticoid receptor-enriched S-49 mouse lymphoma cells

Abstract

A cDNA library from plasma membrane glucocorticoid receptor-enriched (mGR(++)) S- 49 mouse T lymphoma cells was screened with full-length rat intracellular GR (iGR) cDNA, BUGR-2 antibody, and PCR amplimers to portions of the mouse GR cDNA. One or two single-base substitutions resulting in amino acid changes (which do not incapacitate the receptor) were found in all but one clone: Val437 --> Gly (located in the first zinc finger), and Glu546 --> Gly (in the steroid-binding domain). Two previously unidentified exon 1 variants (1D and 1E), and two of three previously reported variants (1A, 1B) were found to be spliced onto the common exon 2. Exon 1D- and 1E-containing transcripts were confirmed by direct sequencing of amplimers from reverse transcriptase-coupled PCR. RNase protection studies revealed that one of these transcripts was expressed in mGR(++) cells only, but not in two mGR-less (mGR(--) S-49, and AtT-20 mouse pituitary) cell lines. These studies suggest that at least four promoters may be responsible for the control of GR (iGR and mGR) types in mouse lymphoma cells.

Transcriptional control of the glucocorticoid receptor: CpG islands, epigenetics and more

“…Expression of the 1A transcripts appears to be limited to the 14 immune system in both humans and rodents. The human 1A3 transcript is widely 15 expressed in both acute lymphoblastic leukemia (ALL) cell lines and in children with this 16 malignancy [16,20,25,[41][42][43]. Similarly, exon 1I is used predominantly in T cells, 17…”

Nongenomic Steroid Action: Controversies, Questions, and Answers

“…The gene encoding the murine GR spans ϳ110 kb, and the transcripts are assembled from nine exons. There are five glucocorticoid receptor transcripts known so far (1A-1E), all differing only at their 5Ј-ends and generated by alternative splice mechanisms in exon 2 (92,93,170,467).…”

Identification, tissue expression, and glucocorticoid responsiveness of alternative first exons of the human glucocorticoid receptor

“…This tissue diversity may partially be due to tissue-specific expression from multiple promoters, resulting in multiple alternative untranslated first exons, of the glucocorticoid receptor (GR). The GR gene (NR3C1, OMIMC138040) contains a presently undetermined number of untranslated first exons that are spliced to a common exon 2 (Strahle et al 1992, Chen et al 1999, McCormick et al 2000, Breslin et al 2001, Zhang et al 2004, Turner & Muller 2005. The resulting differences in 5 0 untranslated regions may add a second level of regulation due to differing posttranscriptional treatment of the resulting mRNAs, potentially influencing mRNA processing, stability, export, and translation (Ayoubi & Van De Ven 1996, Zhang et al 2004.…”

“…The alternative first exons identified thus far are located in two promoter regions, one proximal, spanning about 5 kb upstream of the translation start site, and the second distal, located more than 30 kb further upstream. For the human GR gene, nine untranslated exons have been published thus far (Breslin et al 2001, Turner & Muller 2005, 12 for the rat GR (McCormick et al 2000, Zhang et al 2004, and five for the mouse (Strahle et al 1992, Chen et al 1999. The splice donor sites terminating these first exons are highly conserved between man, mouse, and rat.…”