Project description:We performed RNAseq on total RNA extracted from spleens isolated from mice infected with Orientia tsutsugamushi Karp or Gilliam strains, as well as mock-infected mice to investigate the unique transcriptomic environments elicited by two different Orientia tsutsugamushi strains.
Project description:We performed RNAseq on total RNA extracted from brains of mice infected with Orientia tsutsugamushi to investigate the transcriptomic signature of this tissue throughout infection.
Project description:We performed NanoString analysis on total RNA extracted from spleens of mice infected with Orientia tsutsugamushi to investigate the transcriptomic signature of these cells throughout infection.
Project description:The intracellular bacterium Orientia tsutsugamushi relies on the microtubule cytoskeleton and the motor protein dynein to traffic to the perinuclear region within infected cells. However, it remains unclear how the bacterium is coupled to the dynein machinery and how transport is regulated. Here, we discover that O. tsutsugamushi uses its autotransporter protein ScaC to recruit the dynein adaptors BICD1 and BICD2 for movement to the perinucleus. We show that ScaC is sufficient to engage dynein-based motility in the absence of other bacterial proteins and that BICD1 and BICD2 are required for efficient movement of O. tsutsugamushi during infection. Using TIRF single-molecule assays, we demonstrate that ScaC induces BICD2 to adopt an open conformation which activates the assembly of dynein-dynactin complexes. Our results reveal a role for BICD adaptors during bacterial infection and provide mechanistic insights into the life cycle of an important human pathogen.
Project description:We performed RNAseq on total RNA extracted from splenic B cells isolated from mice infected with Orientia tsutsugamushi to investigate the dynamic transcriptomic signature of these cells throughout infection. We then performed differential expression analysis, meta-analysis, and gene set enrichment anaylsis using data obtained by RNA-seq of mock infected (D0) and O. tsutsugamushi-infected mice (D4 and D8).
Project description:Intracellular pathogens inhibit nuclear factor-κB (NF-κB), the key transcriptional regulator of antimicrobial responses, using incompletely defined mechanisms. NF-κB nuclear localization and gene accessibility is mediated by Ser22-phosphorylated lamin A/C (pSer22-lamin A/C). Here, we report that the obligate intracellular bacterium Orientia tsutsugamushi impairs NF-κB nuclear accumulation by targeting lamin A using a cohort of ankyrin repeat (AR)-containing effectors (Anks) that have a PRANC (pox proteins repeats of ankyrin C-terminal) domain. The Anks’ immunomodulatory capability relies on a hydrophilic peptide that binds lamin A and pSer22-lamin A. Positioning of this peptide in an a-helix between the AR and PRANC domains is functionally essential. O. tsutsugamushi and ectopically expressed Ank1, one of the NF-κB-inhibiting Anks, promote pSer22-lamin A localization to the nucleoplasm. Orientia also alters chromatin to a primarily closed state to limit accessibility at many sites including those regulated by lamin A/pSer22-lamin A along with NF-κB and its coactivator, adapter protein 1. Thus, O. tsutsugamushi synergistically modulates lamin A and chromatin accessibility to counteract NF-κB. These findings reveal a strategy by which an intracellular microbe subverts host immunity, reinforces the regulatory link between lamin A and NF-κB, and indicates that pSer22-lamin A activates NF-κB by increasing chromatin accessibility to it and its coactivators.