Analysis of p53 transactivation domain mutants reveals Acad11 as a metabolic target important for p53 pro-survival function.

The p53 tumor suppressor plays a key role in maintaining cellular integrity. In response to diverse stress signals, p53 can trigger apoptosis to eliminate damaged cells or cell-cycle arrest to enable cells to cope with stress and survive. However, the transcriptional networks underlying p53 pro-survival function are incompletely understood.

Unravelling mechanisms of p53-mediated tumour suppression.

p53 is a crucial tumour suppressor that responds to diverse stress signals by orchestrating specific cellular responses, including transient cell cycle arrest, cellular senescence and apoptosis, which are all processes associated with tumour suppression. However, recent studies have challenged the relative importance of these canonical cellular responses for p53-mediated tumour suppression and have highlighted roles for p53 in modulating other cellular processes, including metabolism, stem cell maintenance, invasion and metastasis, as well as communication within the tumour microenvironment. In this Opinion article, we discuss the roles of classical p53 functions, as well as emerging p53-regulated processes, in tumour suppression.

Global genomic profiling reveals an extensive p53-regulated autophagy program contributing to key p53 responses.

The mechanisms by which the p53 tumor suppressor acts remain incompletely understood. To gain new insights into p53 biology, we used high-throughput sequencing to analyze global p53 transcriptional networks in primary mouse embryo fibroblasts in response to DNA damage. Chromatin immunoprecipitation sequencing reveals 4785 p53-bound sites in the genome located near 3193 genes involved in diverse biological processes.

Measurement of Haemophilus influenzae type a capsular polysaccharide antibodies in cord blood sera.

We measured anti-Haemophilus influenzae type a capsular polysaccharide serum immunoglobulin G antibodies in cord blood sera from Mexican (n = 68) and Chilean mothers (n = 72) by enzyme-linked immunosorbent assay. Measurable antibodies were found in 79.3% of samples.

Deconstructing p53 transcriptional networks in tumor suppression.

p53 is a pivotal tumor suppressor that induces apoptosis, cell-cycle arrest and senescence in response to stress signals. Although p53 transcriptional activation is important for these responses, the mechanisms underlying tumor suppression have been elusive. To date, no single or compound mouse knockout of specific p53 target genes has recapitulated the dramatic tumor predisposition that characterizes p53-null mice.

A shared gene expression signature in mouse models of EBV-associated and non-EBV-associated Burkitt lymphoma.

The link between EBV infection and Burkitt lymphoma (BL) is strong, but the mechanism underlying that link has been elusive. We have developed a mouse model for EBV-associated BL in which LMP2A, an EBV latency protein, and MYC are expressed in B cells. Our model has demonstrated the ability of LMP2A to accelerate tumor onset, increase spleen size, and bypass p53 inactivation.

Epstein-Barr virus in Burkitt's lymphoma: a role for latent membrane protein 2A.

Burkitt's lymphoma (BL) is characterized by translocation of the MYC gene to an immunoglobulin locus. Transgenic mouse models have been used to study the molecular changes that are necessary to bypass tumor suppression in the presence of translocated MYC. Inactivation of the p53 pathway is a major step to tumor formation in mouse models that is also seen in human disease.

Epstein-Barr virus LMP2A bypasses p53 inactivation in a MYC model of lymphomagenesis.

Although Epstein-Barr virus (EBV) is linked to Burkitt's lymphoma (BL), the role of the virus in lymphomagenesis is unclear. LMP2A, encoded by EBV, can be detected in BL biopsies and has prosurvival functions. We generated mice expressing MYC and LMP2A in B cells.

A C-terminal domain targets the Pseudomonas aeruginosa cytotoxin ExoU to the plasma membrane of host cells.

ExoU, a phospholipase injected into host cells by the type III secretion system of Pseudomonas aeruginosa, leads to rapid cytolytic cell death. Although the importance of ExoU in infection is well established, the mechanism by which this toxin kills host cells is less clear. To gain insight into how ExoU causes cell death, we examined its subcellular localization following transfection or type III secretion/translocation into HeLa cells.

Fluorescent multivalent opsonophagocytic assay for measurement of functional antibodies to Streptococcus pneumoniae.

We developed fluorescent mono- and multivalent opsonophagocytic assays (fOPA and fmOPA, respectively) specific for seven Streptococcus pneumoniae serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F). Bacterial survival was quantitated with alamar blue, a fluorescent metabolic indicator. Both fOPA and fmOPA allow for determination of viability endpoints for up to seven serotypes with high levels of agreement to the reference method.