Genes Newly Identified as Regulated by Glucocorticoids in Murine Thymocytes

Abstract

Glucocorticoids induce dramatic biochemical and morphological changes in lymphocytes through an unknown process that requires RNA and protein synthesis. In order to identify genes involved in this response, we previously isolated 11 cDNA clones from the murine WEHI-7TG thymoma cell line that correspond to mRNAs induced by glucocorticoids. We now report the isolation of two new cDNA clones whose gene expression is regulated by glucocorticoids in WEHI-7TG cells. We further characterize the two new cDNA clones, as well as those described previously, by examining the response of each of the corresponding mRNAs to glucocorticoids in murine thymocytes. With the exception of two, all cDNAs correspond to genes that are induced by glucocorticoids in murine thymocytes within 4 h of treatment. We previously identified two of the cDNAs as the mouse VL30 retrovirus-like element and the mouse homolog of chondroitin sulfate proteoglycan core protein. We have now identified four additional cDNA clones that correspond to the genes for calmodulin, mitochondrial phosphate carrier protein, immunoglobulin (Ig)-related glycoprotein (GP-70), and the 70 kilodalton autoantigen for Lupus and Graves diseases. Two other cDNA clones represent previously undescribed genes: one shares a high similarity to known sequences for the family of G-protein-coupled receptors and the other to a human placental-specific protein, PP11. Another cDNA appears to contain sequences for an unknown gene and the remnants of a mouse transposon. ETn. The remaining clones represent new, unidentified genes induced by glucocorticoids in murine thymocytes and in the WEHI-7TG cell line.

Studies of specific gene induction during apoptosis of cell lines conditionally immortalized by SV40

“…This induction is more rapid than that of mdm-2, in agreement with the pro- Table 1 Expression of genes indentified by their diffential expression during apoptosis Gene(s) Induced in Expression in REtsAF Calmodulin, chondroitin sulfate Glucocorticoids induced thymocyte apoptosis [11,20] Not detected proteoglycan core protein RP8 Glutathione S-transferase Ybl Clusterin Ubiquitin Glucocorticoids or radiation induced thymocyte apoptosis [15] Prostate regression [32] and steroid induced lymphocyte apoptosis [21] Prostate regression and various other cell death process [17] Radiation-induced lymphocyte apoptosis [18] and insect muscles degeneration [19] [29], which suggest that, in some cells, p53 can mediate apoptosis by repressing survival genes. Recently, a reevaluation of the role of de novo protein synthesis in thymocyte apoptosis has also suggested that inhibitors of protein synthesis may delay apoptosis rather than prevent it [30], suggesting that some of the components of the apoptotic machinery are already present before apoptosis induction.…”

“…Table 1 summarizes the results obtained with various genes. The genes encoding calmodulin, chondroitin sulfate proteoglycan core protein, ubiquitin and glutathione S-transferase Yb 1, which are induced in apoptotic thymocytes or lymphocytes [11,18,20,21], are not induced during apoptosis of REtsAF.…”

“…10 mg of total RNA was fractionated on 1% agaroseformamide gel and transferred to nylon membrane (HybondN, Amersham) according to [10]. Probes for calmodulin, chondroitin sulfate proteoglycan core protein, clusterin, ubiquitin and GAPDH were obtained, respectively, by labeling of the insert of plasmid p21, p8.5 [11], pSP64-60HE [12], pHUB14.38 [13] and pGAPD-13 [14], respectively, with [32p]dCTP by random primers using the megaprime-labeling systems (Amersham). Probes for RP8, glutathione S-transferase (made from plasmids pRP-8 [15], pGST2 [16]) were labeled with [32p]dCTP by PCR of pBluescript inserts.…”

“…Three types of genes were studied: (1) genes identified during glucocorticoid-induced thymocyte apoptosis (RP-8) [11,15]; (2) during prostate regression and other cell-death processes (clusterin) [17]; and (3) during y irradiation-induced lymphocyte apoptosis [18] and insect muscle degeneration [19] (polyubiquitin). Fig.…”

Interaction of NPY compounds with the rat glucocorticoid-induced receptor (GIR) reveals similarity to the NPY–Y2 receptor

“…GIR was originally identified as a stress-responsive element from the murine T-cell line WEHI-7TG and normal thymocytes treated with glucocorticoids and forskolin [3,10]. Mouse GIR mRNA was detected at high levels in the brain and thymus, and its distribution in brain was found to be enriched in the dorsal and ventral striatum, the forebrain limbic structures and the hypothalamic nuclei [22].…”