DDX3 localizes to the centrosome and prevents multipolar mitosis by epigenetically and translationally modulating p53 expression

Abstract

The DEAD-box RNA helicase DDX3 plays divergent roles in tumorigenesis, however, its function in mitosis is unclear. Immunofluorescence indicated that DDX3 localized to centrosome throughout the cell cycle and colocalized with centrosome-associated p53 during mitosis in HCT116 and U2OS cells. DDX3 depletion promoted chromosome misalignment, segregation defects and multipolar mitosis, eventually leading to G2/M delay and cell death. DDX3 prevented multipolar mitosis by inactivation and coalescence of supernumerary centrosomes. DDX3 silencing suppressed Ser15 phosphorylation of p53 which is required for p53 centrosomal localization. Additionally, knockout of p53 dramatically diminished the association of DDX3 with centrosome, which was rescued by overexpression of the centrosomal targeting-defective p53 S15A mutant, indicating that centrosomal localization of DDX3 is p53 dependent but not through centrosomal location of p53. Furthermore, DDX3 knockdown suppressed p53 transcription through activation of DNA methyltransferases (DNMTs) along with hypermethylation of p53 promoter and promoting the binding of repressive histone marks to p53 promoter. Moreover, DDX3 modulated p53 mRNA translation. Taken together, our study suggests that DDX3 regulates epigenetic transcriptional and translational activation of p53 and colocalizes with p53 at centrosome during mitosis to ensure proper mitotic progression and genome stability, which supports the tumor-suppressive role of DDX3.

Zebrafish Ddx19 deficiency causes serious apoptosis and cell proliferation

“…Here we have shown that the deletion of ddx19 causes abnormal apoptosis and proliferation in zebrafish embryos, and subsequently death. The phenotypes from our ddx19 -/are similar to that of homozygous ddx19 mutants (ddx19 hi1464/hi1464 ), resulting in phenotypic defects and homozygous death [28]. In addition to these findings, we found that the absence of DDX19 caused in the arrest of cells in the S-phase.…”

“…But the defect phenotypes caused by ddx19 -/are more extensive and severe than those caused by of ddx39ab -/-. Nucleoplasm transport factor DDX3 maintains cell cycle and genome stability in HCT116 [28], and our observation of the roles of Ddx19 during development in vivo was similar to it. Therefore, we speculated that the nucleoplasm transport factor in the DEAD-box family may be involved in the regulation of apoptosis and proliferation, which provided a theoretical reference for our further understanding and classify of the family.…”

Global Effects of DDX3 Inhibition on Cell Cycle Regulation Identified by a Combined Phosphoproteomics and Single Cell Tracking Approach

“…Pek, et al previously identified DDX3 to be responsible for chromosomal localization of hCAP-H, a condensin 1 component, and found that inhibition of DDX3 resulted in lagging chromosomes [41] . In addition, a recent paper identified that DDX3 prevents multipolar mitosis by epigenetic transcriptional and translation regulation of p53 [42] . Their findings are in line with our observation that the duration of mitosis is increased after RK-33 treatment.…”

DDX3X is Epigenetically Repressed in Renal Cell Carcinoma and Serves as a Prognostic Indicator and Therapeutic Target in Cancer Progression

“…A study in HCT116 and U2OS cells revealed the modulation of epigenetic transcriptional and translational activation of p53 by DDX3X. DDX3X colocalized with p53 at the mitosis stage of cell cycle to ensure mitotic progression and genome stability, suggesting its role as a tumor suppressor [34]. Interestingly, both the oncogenic and tumor suppressive functions of DDX3X are also reported in the same kind of cancer.…”