Epstein–Barr virus (EBV) is a major contributor to nasopharyngeal carcinoma (NPC) tumorigenesis. Mitochondria have been shown to be a target for tumor viral invasion, and to mediate viral tumorigenesis. In this study, we detected that mitochondrial morphological changes in tumor tissues of NPC patients infected with EBV were accompanied by an elevated expression of BHRF1, an EBV encoded protein homologue to Bcl-2. High expression of BHRF1 in human NPC cell lines enhanced tumorigenesis and metastasis features. With BHRF1 localized to mitochondria, its expression induced cyclophlin D dependent mitochondrial membrane permeabilization transition (MMPT). The MMPT further modulated mitochondrial function, increased ROS production and activated mitophagy, leading to enhanced tumorigenesis. Altogether, our results indicated that EBV-encoded BHRF1 plays an important role in NPC tumorigenesis through regulating cyclophlin D dependent MMPT.

Species of Cronobacter are emerging foodborne pathogens that pose a significant threat to neonates. Functional genomic studies in Cronobacter have been hindered by the lack of efficient genetic manipulation tools. Here, we established a CRISPR/Cas9-based genome editing platform for Cronobacter. We developed a dual-plasmid platform, pAmpCRISPR/pCasCm, by integrating CRISPR/Cas9 with the λ-Red recombination machinery. This platform enables scarless genome editing in Cronobacter malonaticus and proved effective for gene knockout and large-fragment integration under the tested conditions. Furthermore, we validated this platform in another clinically relevant species, Cronobacter sakazakii. The development of this genome editing toolkit provides a useful approach for fundamental research into Cronobacter pathogenesis, such as bacterial physiology studies, drug target exploration, and metabolic engineering.