Gene Expression Regulation of the Type I Interferon-Induced Protein Schlafen 11

We have recently discovered a major role of the type I interferon (IFN‐I)‐induced protein Schlafen (SLFN) 11 in the control of flavivirus infection and verified its effects on HIV‐1. This protein is also relevant in controlling chemosensitivity of cancer in patients, and animal and cellular models. Therefore, understanding the mechanisms regulating SLFN11 expression during infection and chemotherapy is relevant. We have found that infection of human cells by the flavivirus West Nile virus (WNV) or HIV‐1 upregulated the expression of SLFN11. Characterization of the pathways implicated that while WNV increases SLFN11 expression via IFN‐I signaling, HIV‐1 uses an IFN‐I‐independent pathway. To further map the latter signaling pathway, we evaluated the ability of a panel of inflammatory stimuli to induce SLFN11 in primary CD4+ T cells isolated from two healthy donors. Interestingly, phorbol myristate acetate (PMA), ionomycin, and phytohemagglutinin (PHA) potently induced this protein in both donors. These compounds also upregulated SLFN11 expression in cell lines of different histological origin. However, both IFN‐I‐dependent and ‐independent pathways failed to stimulate expression of a 1.3 kb promoter cloned in a gene reporter system, suggesting that this promoter lacks cis ‐acting regulatory elements that are relevant in the regulation of SLFN11 expression in cells. In summary, our data indicate that SLFN11 expression is controlled via IFN‐I‐dependent and ‐ independent pathways. Support or Funding Information Research Initiative for Scientific Enhancement funded by a grant (#R25GM069621‐11) from the National Institute of General SciencesUniversity of Texas at El Paso