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Role of miRNAs in post‐transcriptional gene regulation by high NaCl
Author(s) -
Bravo Ignacio J,
Ferraris Joan D,
Williams Chester K,
Burg Maurice B
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.1001.2
Subject(s) - dicer , microrna , biology , gene expression , messenger rna , microbiology and biotechnology , gene , regulation of gene expression , hek 293 cells , dna microarray , gene silencing , microarray , rna interference , rna , genetics
High NaCl increases mRNA and protein abundance of numerous gene products, including the osmoprotective transcription factor TonEBP/OREBP. High NaCl increases TonEBP/OREBP abundance by stabilizing its mRNA. miRNAs regulate gene expression post‐transcriptionally by destabilizing target mRNAs and inhibiting translation. The purposes of the present studies were 1) to find whether miRNAs regulate TonEBP/OREBP abundance and 2) to identify miRNAs that are regulated by the level of NaCl. DICER and Ago2 are necessary for maturation and activity of miRNAs. We knocked down DICER and Ago2 in HEK293 cells by conditional expression of specific sh_miRNAs. Knocking down either DICER or Ago2 increases TonEBP/OREBP protein abundance, suggesting that miRNAs are involved in its regulation. In order to begin investigating the role of miRNAs in high NaCl‐induced changes of expression of proteins, including TonEBP/OREBP, we conducted a microarray screen of miRNAs affected by high NaCl. We adapted HEK293 cells to 500 mosmol/kg (NaCl added) through many passages or kept them at 300 mosmol/kg. We isolated miRNAs from them with a mirVana Kit, then screened with microarrays containing 470 probes (LC Sciences). Levels of 11 miRNAs are significantly greater at 500 mosmol/kg and 9 are less. Several of these miRNAs have likely target sites in the 3′‐UTRs of TonEBP/OREBP and other tonicity regulated genes. We conclude that the level of NaCl regulates several miRNAs and that these miRNAs may be involved in post‐transcriptional regulation of TonEBP/OREBP and other proteins.