LSD1 is essential for oocyte meiotic progression by regulating CDC25B expression in mice

Mammalian oocytes are arrested at prophase I until puberty when hormonal signals induce the resumption of meiosis I and progression to meiosis II. Meiotic progression is controlled by CDK1 activity and is accompanied by dynamic epigenetic changes. Although the signalling pathways regulating CDK1 activity are well defined, the functional significance of epigenetic changes remains largely unknown. Here we show that LSD1, a lysine demethylase, regulates histone H3 lysine 4 di-methylation (H3K4me2) in mouse oocytes and is essential for meiotic progression. Conditional deletion of Lsd1 in growing oocytes results in precocious resumption of meiosis and spindle and chromosomal abnormalities. Consequently, most Lsd1-null oocytes fail to complete meiosis I and undergo apoptosis. Mechanistically, upregulation of CDC25B, a phosphatase that activates CDK1, is responsible for precocious meiotic resumption and also contributes to subsequent spindle and chromosomal defects. Our findings uncover a functional link between LSD1 and the major signalling pathway governing meiotic progression

Nucleolin functions in nucleolus formation and chromosome congression

Ma N., Matsunaga S., Takata H., et al. Nucleolin functions in nucleolus formation and chromosome congression. Journal of Cell Science, 120, 12, 2091. https://doi.org/10.1242/jcs.008771

PHB2 Protects Sister-Chromatid Cohesion in Mitosis

SummaryCohesion between sister chromatids is essential for proper chromosome segregation in mitosis. In vertebrate mitotic cells, most cohesin is removed from the chromosome arms [1–4], but centromeric cohesin is protected by shugoshin until the onset of anaphase [5]. However, the mechanism of this protection of centromeric cohesion is not well understood. Here, we demonstrate that prohibitin 2 (PHB2) is involved in the regulation of sister-chromatid cohesion during mitosis in HeLa cells. PHB2 is an evolutionarily conserved protein in eukaryotes and has multiple functions, such as transcriptional regulation and cell viability and development [6–8]. However, its functions in mitosis have not yet been determined. We show that depletion of PHB2 by RNA interference (RNAi) causes premature sister-chromatid separation and defects in chromosome congression accompanied by mitotic arrest by spindle-checkpoint activation. In the absence of PHB2, cohesin is dissociated from centromeres during early mitosis, although the centromeric localization of shugoshin is preserved. Thus, our findings suggest that, in addition to the shugoshin, PHB2 is also required to protect the centromeric cohesion from phosphorylation by Plk1 during early mitosis and that its function is essential for proper mitotic progression

ATP redirects cytokine trafficking and promotes novel membrane TNF signaling via microvesicles

Cellular stress or injury induces release of endogenous danger signals such as ATP, which plays a central role in activating immune cells. ATP is essential for the release of nonclassically secreted cytokines such as IL-1β but, paradoxically, has been reported to inhibit the release of classically secreted cytokines such as TNF. Here, we reveal that ATP does switch off soluble TNF (17 kDa) release from LPS-treated macrophages, but rather than inhibiting the entire TNF secretion, ATP packages membrane TNF (26 kDa) within microvesicles (MVs). Secretion of membrane TNF within MVs bypasses the conventional endoplasmic reticulum– and Golgi transport–dependent pathway and is mediated by acid sphingomyelinase. These membrane TNF–carrying MVs are biologically more potent than soluble TNF in vivo, producing significant lung inflammation in mice. Thus, ATP critically alters TNF trafficking and secretion from macrophages, inducing novel unconventional membrane TNF signaling via MVs without direct cell-to-cell contact. These data have crucial implications for this key cytokine, particularly when therapeutically targeting TNF in acute inflammatory diseases.—Soni, S., O'Dea, K. P., Tan, Y. Y., Cho, K., Abe, E., Romano, R., Cui, J., Ma, D., Sarathchandra, P., Wilson, M. R., Takata, M. ATP redirects cytokine trafficking and promotes novel membrane TNF signaling via microvesicles. FASEB J. 33, 6442–6455 (2019). www.fasebj.org

An introduction to superhydrophobicity

This paper is derived from a training session prepared for COST P21. It is intended as an introduction to superhydrophobicity to scientists who may not work in this area of physics or to students. Superhydrophobicity is an effect where roughness and hydrophobicity combine to generate unusually hydrophobic surfaces, causing water to bounce and roll off as if it were mercury and is used by plants and animals to repel water, stay clean and sometimes even to breathe. The effect is also known as The Lotus Effect® and Ultrahydrophobicity. In this paper we introduce many of the theories used, some of the methods used to generate surfaces and then describe some of the implications of the effect

Evolutionary relationships among barley and <i>Arabidopsis</i> core circadian clock and clock-associated genes

The circadian clock regulates a multitude of plant developmental and metabolic processes. In crop species, it contributes significantly to plant performance and productivity and to the adaptation and geographical range over which crops can be grown. To understand the clock in barley and how it relates to the components in the Arabidopsis thaliana clock, we have performed a systematic analysis of core circadian clock and clock-associated genes in barley, Arabidopsis and another eight species including tomato, potato, a range of monocotyledonous species and the moss, Physcomitrella patens. We have identified orthologues and paralogues of Arabidopsis genes which are conserved in all species, monocot/dicot differences, species-specific differences and variation in gene copy number (e.g. gene duplications among the various species). We propose that the common ancestor of barley and Arabidopsis had two-thirds of the key clock components identified in Arabidopsis prior to the separation of the monocot/dicot groups. After this separation, multiple independent gene duplication events took place in both monocot and dicot ancestors. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00239-015-9665-0) contains supplementary material, which is available to authorized users