Glucocorticoid-induced alternative promoter usage for a novel 5′ variant of granzyme A

Abstract

Glucocorticoids exert diverse physiological functions through transcriptional regulation of genes including granzyme A (GZMA). GZMA is one of the apoptotic effectors localized in cytotoxic T lymphocytes and is considered to mediate glucocorticoidinduced apoptosis of human leukemia 697 cells. In the present study, we identified a novel 5¢ variant transcript of GZMA in dexamethasone (DEX)-treated 697 cells. We designated this novel transcript as GZMAb. The transcription of GZMAb starts at 290 bp downstream of the first intronic glucocorticoid response element (GRE). Chromatin immunoprecipitation assay showed that glucocorticoid receptor (GR) binds to the intronic GRE in a DEX-dependent manner. Luciferase assay and RT-PCR also showed that DEX induces GZMAb transcription mediated by GR binding to the intronic GRE. Our results show that there exist at least two transcripts in human GZMA, whose expression is differentially regulated by glucocorticoid.

Identification of Thyroid Hormone Receptor Binding Sites and Target Genes Using ChIP-on-Chip in Developing Mouse Cerebellum

“…Similarly, the expression of hepatic carnitine palmitoyltransferase-I alpha, an enzyme involved in fatty acid metabolism, is regulated by TR action at a TRE located in the first intron [40]. Intronic locations of transcriptional regulatory sites appear to be common for a variety of nuclear receptors including the androgen receptor [41], glucocorticoid receptor [42], vitamin D3 [43] and PPAR gamma [44]. Likewise, between 38 and 47% of estrogen receptor binding sites are located within introns [45], [46].…”

Death by a Thousand Cuts: Granzyme Pathways of Programmed Cell Death

“…Further study of the GzmA promoter did not find a glucocorticoid responsive element (GRE) upstream of the transcriptional start site, but did find a GRE in the first intron (42). In fact, a novel 5′ variant GzmA transcript starts 290 bp downstream of this intronic GRE (45). These alternative promoters generate two GzmA transcripts with different first exons (exon1a and 1b).…”

“…GzmA transcripts isolated from CTL contain exon1a, which encodes an N-terminal leader peptide to direct the nascent protein into the lumen of the endoplasmic reticulum (ER). Glucocorticoid treatment induces the exon1b-containing transcript and also suppresses the exon1a transcript (45). The exon1b encodes a shorter leader peptide, which may cause aberrant subcellular localization of mature GzmA.…”

Granzyme A Deficiency Breaks Immune Tolerance and Promotes Autoimmune Diabetes Through a Type I Interferon–Dependent Pathway

“…We suggest that this is a cell-intrinsic process where granzyme A is released from endolysosomal storage granules into the cytosol, as described for granzyme B (46,47). Alternatively, an intronic promoter that can be activated by dexamethoasone induces transcription of a granzyme A isoform lacking a signal peptide, which would be produced in the cytosol (48). If folded correctly and functional, this form would have direct access to the SET complex.…”