Lysine demethylases KDM6A and UTY: the X and Y of histone demethylation

Histone demethylases remove transcriptional repressive marks from histones in the nucleus. KDM6A (also known as UTX) is a lysine demethylase which acts on the trimethylated lysine at position 27 in histone 3. The KDM6A gene is located on the X chromosome but escapes X inactivation even though it is not located in the pseudoautosomal region. There is a homologue of KDM6A on the Y chromosome, known as UTY. UTY was thought to have lost its demethylase activity and to represent a non-functional remnant of the ancestral KDM6A gene. However, results with knockout mice suggest that the gene is expressed and the protein performs some function within the cell. Female mice with homozygous deletion of Kdm6a do not survive, but hemizygous males are viable, attributed to the presence of the Uty gene. KDM6A is mutated in the human condition Kabuki syndrome type 2 (OMIM 300867) and in many cases of cancer. The amino acid sequence of KDM6A has been conserved across animal phyla, although it is only found on the X chromosome in eutherian mammals. In this review, we reanalyse existing data from various sources (protein sequence comparison, evolutionary genetics, transcription factor binding and gene expression analysis) to determine the function, expression and evolution of KDM6A and UTY and show that UTY has a functional role similar to KDM6A in metabolism and development

A Survey Assessment of Pediatric Nurses’ Disaster Preparedness

The training programs for disasters in the US are fragmented, uncoordinated, and poorly defined. The purpose of this study was to assess the perceived disaster preparedness of inpatient nurses at a Midwestern level 1 pediatric trauma center. The Disaster Preparedness Evaluation Tool was used to assess disaster preparedness, response abilities, recovery preparedness, and overall preparedness. The Theory of Self-Efficacy was applied to disaster preparedness in this study. Performance accomplishments were conceptualized as prior disaster experience and level of education, vicarious experience as training and drills, verbal persuasion as nurse manager or staff nurse role, and emotional arousal as department/unit type (Emergency Department (ED) or non-Emergency Department). The three main areas addressed in the study included the level of preparedness among inpatient pediatric nurses, the influence of unit type on preparedness, and factors that impact preparedness. Levels of preparedness were compared by unit type (ED and non-ED), previous disaster experience, and disaster education. There were statistically significant differences between ED and non-ED nurses for all four dependent variables (disaster preparedness, response abilities, recovery preparedness, and overall preparedness), and unit type was a statistically significant positive predictor of disaster preparedness, response abilities, and overall preparedness. Disaster education was a positive predictor of response abilities, recovery preparedness, and overall preparedness and participation in a disaster was a positive predictor of response abilities and overall preparedness. Overall, study findings indicated that nurses were not well-prepared for a disaster. Theoretical implications of the study include the conduction of theory-based disaster nursing research, as well as national policies on training and education

Roles of the kinase TAK1 in TRAF6-dependent signaling by CD40 and its oncogenic viral mimic, LMP1.

The Epstein-Barr virus (EBV)-encoded protein latent membrane protein 1 (LMP1) is essential for EBV-mediated B cell transformation and plays a critical role in the development of post-transplant B cell lymphomas. LMP1 also contributes to the exacerbation of autoimmune diseases such as systemic lupus erythematosus (SLE). LMP1 is a functional mimic of the tumor necrosis factor receptor (TNFR) superfamily member CD40, and relies on TNFR-associated factor (TRAF) adaptor proteins to mediate signaling. However, LMP1 activation signals to the B cell are amplified and sustained compared to CD40 signals. We previously demonstrated that LMP1 and CD40 use TRAF molecules differently. Although associating with CD40 and LMP1 via separate mechanisms, TRAF6 plays a significant role in signal transduction by both. It is unknown whether TRAF6 mediates CD40 versus LMP1 functions via distinct or shared pathways. In this study, we tested the hypothesis that TRAF6 uses the kinase TAK1 to trigger important signaling pathways following both CD40 and LMP1 stimulation. We determined that TAK1 was required for JNK activation and interleukin-6 (IL-6) production mediated by CD40 and LMP1, in both mouse and human B cells. Additionally, TRAF3 negatively regulated TRAF6-dependent, CD40-mediated TAK1 activation by limiting TRAF6 recruitment. This mode of regulation was not observed for LMP1 and may contribute to the dysregulation of LMP1 compared to CD40 signals

Histone demethylases in physiology and cancer : a tale of two enzymes, JMJD3 and UTX

Gene regulation is fine-tuned by a dynamic balance between transcriptionally activating and repressive modifications of histone tails. It has been well-established that lysine and arginine methylation can be reversed by two groups of evolutionarily conserved enzymes known as histone demethylases, which have been shown to play critical roles in development, differentiation and diseases like cancer. Recent work has demonstrated demethylase-independent functions of these proteins, highlighting the complex mechanisms by which these proteins exert their effects on gene expression. Here, we discuss the roles of lysine 27 demethylases, JMJD3 and UTX, in cancer and potential therapeutic avenues targeting these enzymes. Despite a high degree of sequence similarity in the catalytic domain between JMJD3 and UTX, numerous studies revealed surprisingly contrasting roles in cellular reprogramming and cancer, particularly leukemia. Understanding the demethylase-dependent and demethylase-independent functions of the enzymes affecting histone methylation, their post-translational modifications and participation in different complexes, as well as in vivo modeling of the mutations affecting those enzymes in cancer, can shed light on their unique physiological roles. This information cumulated in the future will aid in the development of improved inhibitors to treat cancers affected by demethylase mutations and aberrant gene activation

Role of TAK1 in CD40 and LMP1 early signaling events.

<p>A) Mouse CH12.LX B cells were treated with DMSO or TAK1i for 30 min prior to stimulation with anti-mCD40 Ab for 0, 2, 5, 10, or 30 min. Western blots show pTAK1, pJNK, pIκBα, and total IκBα, with total JNK and actin as loading controls. B) Similar to panel <i>A</i>, except that CH12.hCD40LMP1 mouse B cells were stimulated with anti-hCD40 Ab for 0, 10, 30, or 60 min. Data shown are representative of three independent experiments.</p

Role of TAK1 in IL-6 production by CD40 and LMP1.

<p>A) WT mouse splenic B cells were treated with DMSO or TAK1i prior to stimulation with control insect cells (control i) or those expressing mCD154 (mCD154 i), as described in Methods. Cells were cultured for 24 h and supernatants were collected for IL-6 ELISAs. B) Similar to panel <i>A</i>, except that B cells were from a mCD40LMP1 Tg mouse. C) Similar to panel <i>A</i>, except that human B cells were stimulated. D) Similar to panel <i>A</i>, except that CH12.hCD40LMP1 mouse B cells were treated with medium alone (control) or IPTG to induce DN-TAK1 prior to stimulation. Data in all panels are mean values ± SEM of triplicate samples, and are representative of at least two independent experiments.</p

Requirement of TAK1 in CD40- and LMP1-mediated Ab production.

<p>CH12.hCD40 or CH12.hCD40LMP1 cells were treated with medium alone or IPTG for 18 h to induce DN-TAK1 prior to stimulation with anti-CD40 Abs, where anti-mCD40 Ab induced signaling by endogenous mCD40, and anti-hCD40 Ab induced signaling via either hCD40 (left) or hCD40LMP1 (right). After 72 h, samples were assayed for IgM production by hemolytic plaque assay. Data are presented as plaque-forming cells (Pfc, IgM-producing cells) per 10⁶ viable recovered cells, mean values ± SEM of replicate samples, and are representative of 3 independent experiments.</p

Requirement of TRAFs in CD40-mediated TAK1 activation.

<p>A) A20.TRAF3^+/+ or A20.TRAF3^−/− mouse B cells were stimulated with anti-mCD40 Ab for 0, 5, 10, or 30 min. Western blots show pTAK1 and TRAF3, with actin as a loading control. B) Similar to panel <i>A</i>, except that A20.TRAF6^+/+ or A20.TRAF6^−/− mouse B cells were used. Western blots show pTAK1 and TRAF6, with actin as a loading control. These images were part of the same membrane, but the middle lanes were omitted here for clarity. Data shown are representative of at least four independent experiments.</p