Maternal epigenetic factors in embryonic and postnatal development.

Maternal factors present in oocytes and surrounding granulosa cells influence early development of embryos. In this study, we searched for epigenetic regulators that are expressed in oocytes and/or granulosa cells. Some of the 120 epigenetic regulators examined were expressed specifically in oocytes and/or granulosa cells. When their expression was examined in young versus aged oocytes or granulosa cells, many were significantly up- or downregulated in aged cells. The maternal role of six genes in development was investigated by generating oocyte-specific knock-out (MKO) mice. Two genes (Mllt10, Kdm2b) did not show maternal effects on later development, whereas maternal effects were evident for Kdm6a, Kdm4a, Prdm3, and Prdm16 for MKO female mice. Offspring from Kdm6a MKO mice underwent perinatal lethality at a higher rate. Pups derived from Prdm3;Prdm16 double MKO showed a higher incidence of postnatal death. Finally, embryos derived from Kdm4a MKO mice showed early developmental defects as early as the peri-implantation stage. These results suggest that many of maternal epigenetic regulators undergo differential expression upon aging. Some, such as Kdm4a, Kdm6a, Prdm3, and Prdm16, have maternal role in later embryonic or postnatal development.

Long-term prognosis after stapled and hand-sewn ileal pouch-anal anastomoses for familial adenomatous polyposis: a multicenter retrospective study.

PURPOSE: The long-term prognosis of stapled and hand-sewn ileal pouch-anal anastomoses in familial adenomatous polyposis patients in Japan remains unknown. This study aimed to compare the overall survival in familial adenomatous polyposis patients who underwent stapled or hand-sewn ileal pouch-anal anastomosis. METHODS: This multicenter retrospective study was conducted at 12 institutions in Shizuoka Prefecture, Japan. The clinical outcomes of 53 eligible familial adenomatous polyposis patients who underwent stapled (n = 24) and hand-sewn (n = 29) ileal pouch-anal anastomosis were compared. RESULTS: The median follow-up duration was 171.5 months. The incidence of adenoma in the remnant rectum or anal transitional zone and metachronous rectal cancer was significantly more common in stapled ileal pouch-anal anastomosis (adenoma: stapled, 45.8%, vs. hand-sewn, 10.3%, p = 0.005; metachronous rectal cancer: 29.2%, vs. none, p = 0.002). The number of deaths was remarkably higher in stapled ileal pouch-anal anastomosis (p = 0.002). Metachronous rectal cancer was the most common cause of death. Overall survival was worse in stapled ileal pouch-anal anastomosis than in hand-sewn ileal pouch-anal anastomosis (120 months, 90.7% vs. 96.6%; 240 months, 63.7% vs. 96.6%; p = 0.044). Cox regression analysis revealed the independent effects of preoperative advanced colorectal cancer and stapled ileal pouch-anal anastomosis on overall survival. CONCLUSION: Stapled ileal pouch-anal anastomosis negatively affected the overall survival of familial adenomatous polyposis patients. Therefore, hand-sewn ileal pouch-anal anastomosis is recommended for better prognosis in these patients.

Validation and comparison of prognostic scoring systems in patients with head and neck squamous cell carcinoma treated with nivolumab.

OBJECTIVE: Several scoring systems have been developed to predict prognosis in patients with refractory cancer. We aimed to validate eight scoring systems and determine the best method for predicting the prognosis of head and neck squamous cell carcinoma treated with nivolumab. METHODS: This multicentre retrospective study involved 154 patients with recurrent and/or metastatic head and neck squamous cell carcinoma treated with nivolumab between 2017 and 2020. Oncological outcomes were assessed according to the scoring systems, including MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio and Hammersmith scores. Objective response, overall survival and progression-free survival were evaluated using logistic regression and Cox proportional hazards analyses. Receiver operating curve analysis was used to calculate the area under the curve and estimate the efficacy of each score. RESULTS: No significant associations were found between the responses and any score. Seven of the eight scoring systems were associated with disease control (odds ratio, 0.26-0.70). Amongst the eight scoring systems, MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio showed the highest area under the curve for predicting response and disease control. Seven scoring systems were prognostic factors for progression-free survival (hazard ratio, 1.22-1.95). All eight scoring systems were prognostic factors for overall survival (hazard ratio, 1.62-3.83). According to the time-dependent receiver operating characteristics analysis for overall survival, the Hammersmith scoring system had the best predictive ability at 3 months, and the MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio scoring system had the highest area under the curve between 6 and 24 months. CONCLUSIONS: MD Anderson Cancer Center + neutrophil-to-lymphocyte ratio and Hammersmith scoring systems were better predictors of prognosis in patients with head and neck squamous cell carcinoma treated with nivolumab.

PABPN1L is required for maternal mRNA degradation after meiosis resumption.

Poly(A)-binding proteins (PABPs) play roles in mRNA maturation, translational activity, and decay. The functions of PABPs, especially PABPN1 and PABPC1, in somatic cells have been well-studied. However, little is known about the roles of PABPs in oocytes because of the unique mechanisms of mRNA metabolism in oocytes. This study focused on PABPN1L and generated Pabpn1l knockout (KO) mice using the CRISPR/Cas9 system. After mating tests, we found that Pabpn1l KO females were infertile due to the failure of the embryos to develop to the 4-cell stage. RNA-seq analysis revealed aberrant mRNA persistence in Pabpn1l KO-MII oocytes, which indicates impaired mRNA degradation during the germinal vesicle (GV) to MII transition. We also revealed that the exogenous expression of Pabpn1l mRNA in KO-GV oocytes recovered defects of embryonic development. PABPN1L is partly indispensable for female fertility in mice, owing to its necessity for embryonic development, which is supported by mRNA degradation during GV to MII maturation.

Fungal effector SIB1 of Colletotrichum orbiculare has unique structural features and can suppress plant immunity in Nicotiana benthamiana.

Fungal plant pathogens secrete virulence-related proteins, called effectors, to establish host infection; however, the details are not fully understood yet. Functional screening of effector candidates using Agrobacterium-mediated transient expression assay in Nicotiana benthamiana identified two virulence-related effectors, named SIB1 and SIB2 (Suppression of Immunity in N. benthamiana), of an anthracnose fungus Colletotrichum orbiculare, which infects both cucurbits and N. benthamiana. The Agrobacterium-mediated transient expression of SIB1 or SIB2 increased the susceptibility of N. benthamiana to C. orbiculare, which suggested these effectors can suppress immune responses in N. benthamiana. The presence of SIB1 and SIB2 homologs was found to be limited to the genus Colletotrichum. SIB1 suppressed both (i) the generation of reactive oxygen species triggered by two different pathogen-associated molecular patterns, chitin and flg22, and (ii) the cell death response triggered by the Phytophthora infestans INF1 elicitin in N. benthamiana. We determined the NMR-based structure of SIB1 to obtain its structural insights. The three-dimensional structure of SIB1 comprises five ß-strands, each containing three disulfide bonds. The overall conformation was found to be a cylindrical shape, such as the well-known antiparallel ß-barrel structure. However, the ß-strands were found to display a unique topology, one pair of these ß-strands formed a parallel ß-sheet. These results suggest that the effector SIB1 present in Colletotrichum fungi has unique structural features and can suppress pathogen-associated molecular pattern-triggered immunity in N. benthamiana.

Conserved fungal effector suppresses PAMP-triggered immunity by targeting plant immune kinases.

Plant pathogens have optimized their own effector sets to adapt to their hosts. However, certain effectors, regarded as core effectors, are conserved among various pathogens, and may therefore play an important and common role in pathogen virulence. We report here that the widely distributed fungal effector NIS1 targets host immune components that transmit signaling from pattern recognition receptors (PRRs) in plants. NIS1 from two Colletotrichum spp. suppressed the hypersensitive response and oxidative burst, both of which are induced by pathogen-derived molecules, in Nicotiana benthamianaMagnaporthe oryzae NIS1 also suppressed the two defense responses, although this pathogen likely acquired the NIS1 gene via horizontal transfer from Basidiomycota. Interestingly, the root endophyte Colletotrichum tofieldiae also possesses a NIS1 homolog that can suppress the oxidative burst in N. benthamiana We show that NIS1 of multiple pathogens commonly interacts with the PRR-associated kinases BAK1 and BIK1, thereby inhibiting their kinase activities and the BIK1-NADPH oxidase interaction. Furthermore, mutations in the NIS1-targeting proteins, i.e., BAK1 and BIK1, in Arabidopsis thaliana also resulted in reduced immunity to Colletotrichum fungi. Finally, M. oryzae lacking NIS1 displayed significantly reduced virulence on rice and barley, its hosts. Our study therefore reveals that a broad range of filamentous fungi maintain and utilize the core effector NIS1 to establish infection in their host plants and perhaps also beneficial interactions, by targeting conserved and central PRR-associated kinases that are also known to be targeted by bacterial effectors.

Red-Beet Betalain Pigments Inhibit Amyloid-ß Aggregation and Toxicity in Amyloid-ß Expressing Caenorhabditis elegans.

Betalain pigments are mainly produced by plants belonging to the order of Caryophyllales. Betalains exhibit strong antioxidant activity and responds to environmental stimuli and stress in plants. Recent reports of antioxidant, anti-inflammatory and anti-cancer properties of betalain pigments have piqued interest in understanding their biological functions. We investigated the effects of betalain pigments (betanin and isobetanin) derived from red-beet on amyloid-ß (Aß) aggregation, which causes Alzheimer's disease. Non-specific inhibition of Aß aggregation against Aß40 and Aß42 by red-beet betalain pigments, in vitro was demonstrated using the thioflavin t fluorescence assay, circular dichroism spectroscopy analysis, transmission electron microscopy and nuclear magnetic resonance (NMR) analysis. Furthermore, we examined the ability of red-beet betalain pigments to interfere with Aß toxicity by using the transgenic Caenorhabditis elegans model, which expresses the human Aß42 protein intracellularly within the body wall muscle. It responds to Aß-toxicity with paralysis and treatment with 50 µM red-beet betalain pigments significantly delayed the paralysis of C. elegans. These results suggest that betalain pigments reduce Aß-induced toxicity.

[A patient with autoimmune pancreatitis complicated by pancreatic pseudocyst that caused colonic perforation-induced gastrointestinal bleeding].

A 62-year-old male patient was referred to our hospital for jaundice and bloody feces. He had hyper-IgG4-emia. Computed tomography (CT) showed diffuse pancreatic enlargement, pancreatic pseudocyst, and hematoma of the splenic flexure of the colon. Magnetic resonance imaging (MRI) showed a fistula in the pancreatic pseudocyst and splenic flexure of the colon. Moreover, lower gastrointestinal endoscopy showed a fistula in the same region. Endoscopic retrograde cholangiopancreatography (ERCP) showed narrowing of the main pancreatic duct and stenosis of the lower bile duct. Following this, the patient was diagnosed with autoimmune pancreatitis-induced pancreatic pseudocyst and colonic perforation-induced gastrointestinal bleeding. The pancreatic pseudocyst and fistula were resolved through steroid treatment.

Similarities and differences in the conformational stability and reversibility of ORF8, an accessory protein of SARS-CoV-2, and its L84S variant.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has the characteristic accessory protein ORF8. Although clinical reports indicate that ORF8 variant strains (Δ382 and L84S variants) are less likely to cause severe illness, functional differences between wild-type and variant ORF8 are unknown. Furthermore, the physicochemical properties of the ORF8 protein have not been analyzed. In this study, the physicochemical properties of the wild-type ORF8 and its L84S variant were analyzed and compared. Using the tobacco BY-2 cell production system, which has been successfully used to produce the wild-type ORF8 protein with a single conformation, was used to successfully produce the ORF8 L84S variant protein at the same level as wild-type ORF8. The produced proteins were purified, and their temperature and pH dependencies were examined using nuclear magnetic resonance spectra. Our data suggested that the wild-type and L84S variant ORF8 structures are highly stable over a wide temperature range. Both proteins displayed an aggregated conformation at higher temperature that reverted when the temperature was decreased to room temperature. Moreover, ORF8 precipitated at acidic pH and this precipitation was reversed when the solution pH was shifted to neutral. Interestingly, the L84S variant exhibited greater solubility than wild-type ORF8 under acidic conditions. Thus, the finding indicated that conformational stability and reversibility of ORF8 are key properties related to function in oppressive environments.

Production of ORF8 protein from SARS-CoV-2 using an inducible virus-mediated expression system in suspension-cultured tobacco BY-2 cells.

KEY MESSAGE: Production of ORF8 protein from SARS-CoV-2 in tobacco BY-2 cells.

Sat-BSA: an NGS-based method using local de novo assembly of long reads for rapid identification of genomic structural variations associated with agronomic traits.

Advances in next generation sequencing (NGS)-based methodologies have accelerated the identifications of simple genetic variants such as point mutations and small insertions/deletions (InDels). Structural variants (SVs) including large InDels and rearrangements provide vital sources of genetic diversity for plant breeding. However, their analysis remains a challenge due to their complex nature. Consequently, novel NGS-based approaches are needed to rapidly and accurately identify SVs. Here, we present an NGS-based bulked-segregant analysis (BSA) technique called Sat-BSA (SVs associated with traits) for identifying SVs controlling traits of interest in crops. Sat-BSA targets allele frequencies at all SNP positions to first identify candidate genomic regions associated with a trait, which is then reconstructed by long reads-based local de novo assembly. Finally, the association between SVs, RNA-seq-based gene expression patterns and trait is evaluated for multiple cultivars to narrow down the candidate genes. We applied Sat-BSA to segregating F2 progeny obtained from crosses between turnip cultivars with different tuber colors and successfully isolated two genes harboring SVs that are responsible for tuber phenotypes. The current study demonstrates the utility of Sat-BSA for the identification of SVs associated with traits of interest in species with large and heterozygous genomes.

Ca2+-dependent interaction between calmodulin and CoDN3, an effector of Colletotrichum orbiculare.

Nuclear magnetic resonance (NMR) data directly indicated a Ca2+-dependent interaction between calmodulin (CaM) and CoDN3, a small effector of the plant pathogenic fungus Colletotrichum orbiculare, which is the causal agent of cucumber anthracnose. The overall conformation of CoDN3 is intrinsically disordered, and the CaM-binding site spans residues 34-53 of its C-terminal region. Experiments employing a chemically synthesized peptide corresponding to the CaM-binding site indicated that the CaM-binding region of CoDN3 in the Ca2+-bound CaM complex takes an α-helical conformation. Cell death suppression assay using a CoDN3 mutant lacking the CaM-binding ability suggested that the wild type CaM-binding site is necessary for full CoDN3 function in vivo.

Isolation of amaranthin synthetase from Chenopodium quinoa and construction of an amaranthin production system using suspension-cultured tobacco BY-2 cells.

Betalains are plant pigments primarily produced by plants of the order Caryophyllales. Because betalain possesses anti-inflammatory and anticancer activities, it may be useful as a pharmaceutical agent and dietary supplement. Recent studies have identified the genes involved in the betalain biosynthesis of betanin. Amaranthin and celosianin II are abundant in the quinoa (Chenopodium quinoa Willd.) hypocotyl, and amaranthin comprises glucuronic acid bound to betanin; therefore, this suggests the existence of a glucuronyltransferase involved in the synthesis of amaranthin in the quinoa hypocotyl. To identify the gene involved in amaranthin biosynthesis, we performed a BLAST analysis and phylogenetic tree analysis based on sequences homologous to flavonoid glycosyltransferase, followed by expression analysis on the quinoa hypocotyl to obtain three candidate proteins. Production of amaranthin in a transient Nicotiana benthamiana expression system was evaluated for these candidates and one was identified as having the ability to produce amaranthin. The gene encoding this protein was quinoa amaranthin synthetase 1 (CqAmaSy1). We also created a transgenic tobacco bright yellow-2 (BY-2) cell line wherein four betalain biosynthesis genes were introduced to facilitate amaranthin production. This transgenic cell line produced 13.67 ± 4.13 µm (mean ± SEM) amaranthin and 26.60 ± 1.53 µm betanin, whereas the production of isoamaranthin and isobetanin could not be detected. Tests confirmed the ability of amaranthin and betanin to slightly suppress cancer cell viability. Furthermore, amaranthin was shown to significantly inhibit HIV-1 protease activity, whereas betanin did not.

Genome engineering uncovers 54 evolutionarily conserved and testis-enriched genes that are not required for male fertility in mice.

Gene-expression analysis studies from Schultz et al. estimate that more than 2,300 genes in the mouse genome are expressed predominantly in the male germ line. As of their 2003 publication [Schultz N, Hamra FK, Garbers DL (2003) Proc Natl Acad Sci USA 100(21):12201-12206], the functions of the majority of these testis-enriched genes during spermatogenesis and fertilization were largely unknown. Since the study by Schultz et al., functional analysis of hundreds of reproductive-tract-enriched genes have been performed, but there remain many testis-enriched genes for which their relevance to reproduction remain unexplored or unreported. Historically, a gene knockout is the "gold standard" to determine whether a gene's function is essential in vivo. Although knockout mice without apparent phenotypes are rarely published, these knockout mouse lines and their phenotypic information need to be shared to prevent redundant experiments. Herein, we used bioinformatic and experimental approaches to uncover mouse testis-enriched genes that are evolutionarily conserved in humans. We then used gene-disruption approaches, including Knockout Mouse Project resources (targeting vectors and mice) and CRISPR/Cas9, to mutate and quickly analyze the fertility of these mutant mice. We discovered that 54 mutant mouse lines were fertile. Thus, despite evolutionary conservation of these genes in vertebrates and in some cases in all eukaryotes, our results indicate that these genes are not individually essential for male mouse fertility. Our phenotypic data are highly relevant in this fiscally tight funding period and postgenomic age when large numbers of genomes are being analyzed for disease association, and will prevent unnecessary expenditures and duplications of effort by others.

PYK10 myrosinase reveals a functional coordination between endoplasmic reticulum bodies and glucosinolates in Arabidopsis thaliana.

The endoplasmic reticulum body (ER body) is an organelle derived from the ER that occurs in only three families of the order Brassicales and is suggested to be involved in plant defense. ER bodies in Arabidopsis thaliana contain large amounts of ß-glucosidases, but the physiological functions of ER bodies and these enzymes remain largely unclear. Here we show that PYK10, the most abundant ß-glucosidase in A. thaliana root ER bodies, hydrolyzes indole glucosinolates (IGs) in addition to the previously reported in vitro substrate scopolin. We found a striking co-expression between ER body-related genes (including PYK10), glucosinolate biosynthetic genes and the genes for so-called specifier proteins affecting the terminal products of myrosinase-mediated glucosinolate metabolism, indicating that these systems have been integrated into a common transcriptional network. Consistent with this, comparative metabolite profiling utilizing a number of A. thaliana relatives within Brassicaceae identified a clear phylogenetic co-occurrence between ER bodies and IGs, but not between ER bodies and scopolin. Collectively, our findings suggest a functional link between ER bodies and glucosinolate metabolism in planta. In addition, in silico three-dimensional modeling, combined with phylogenomic analysis, suggests that PYK10 represents a clade of 16 myrosinases that arose independently from the other well-documented class of six thioglucoside glucohydrolases. These findings provide deeper insights into how glucosinolates are metabolized in cruciferous plants and reveal variation of the myrosinase-glucosinolate system within individual plants.

Isolation and characterization of the betalain biosynthesis gene involved in hypocotyl pigmentation of the allotetraploid Chenopodium quinoa.

In quinoa seedlings, the pigment betalain accumulates in the hypocotyl. To isolate the genes involved in betalain biosynthesis in the hypocotyl, we performed ethyl methanesulfonate (EMS) mutagenesis on the CQ127 variety of quinoa seedlings. While putative amaranthin and celosianin II primarily accumulate in the hypocotyls, this process produced a green hypocotyl mutant (ghy). This MutMap+ method using the quinoa draft genome revealed that the causative gene of the mutant is CqCYP76AD1-1. Our results indicated that the expression of CqCYP76AD1-1 was light-dependent. In addition, the transient expression of CqCYP76AD1-1 in Nicotiana benthamiana leaves resulted in the accumulation of betanin but not isobetanin, and the presence of a polymorphism in CqCYP76A1-2 in the CQ127 variety was shown to have resulted in its loss of function. These findings suggested that CqCYP76AD1-1 is involved in betalain biosynthesis during the hypocotyl pigmentation process in quinoa. To our knowledge, CqCYP76AD1-1 is the first quinoa gene identified by EMS mutagenesis using a draft gene sequence.

Aldo-keto reductase family 1 member B10 is associated with hepatitis B virus-related hepatocellular carcinoma risk.

AIM: Recent reports have indicated that aldo-keto reductase family 1 member B10 (AKR1B10), a cancer-related oxidoreductase, was upregulated in some chronic liver diseases. However, few studies have reported AKR1B10 expression in chronic hepatitis B virus (HBV)-infected patients. The aim of the present study was to analyze AKR1B10 expression and its relevance on hepatocellular carcinoma (HCC) development in patients with chronic HBV infection. METHODS: Expression of AKR1B10 in the liver of 119 chronic HBV-infected patients was assessed and quantified immunohistochemically. A multivariate Cox model was used to estimate the hazard ratios of AKR1B10 expression for HCC development. The cumulative incidences of HCC were evaluated using Kaplan-Meier analysis. RESULTS: Expression of AKR1B10 in the study cohort ranged from 0% to 84%. During the median follow-up time (6.2 years), 13 patients developed HCC. Multivariate analysis revealed that high AKR1B10 expression (≥15%) was an independent risk factor for HCC (hazard ratio, 10.8; 95% confidence interval, 3.0-38.6; P < 0.001). The 5-year cumulative incidences of HCC were 20.6% and 2.6% in patients with high and low AKR1B10 expression, respectively (P < 0.001). Patients with high AKR1B10 expression had significantly higher alanine aminotransferase levels during follow-up than those with low expression, even though antiviral treatment decreased HBV-DNA levels in both groups. CONCLUSION: Chronic HBV-infected patients with high hepatic AKR1B10 expression had an increased risk of HCC development. This suggests that AKR1B10 upregulation might play a role in the early stages of HBV-related hepatocarcinogenesis.

Impact of aldo-keto reductase family 1 member B10 on the risk of hepatitis C virus-related hepatocellular carcinoma.

BACKGROUND AND AIM: Aldo-keto reductase family 1 member B10 (AKR1B10), a cancer-related oxidoreductase, was recently reported to be upregulated in some chronic liver diseases. However, its relevance in hepatocellular carcinoma (HCC) development is not fully assessed, especially in patients with chronic hepatitis C virus (HCV) infection. METHODS: Aldo-keto reductase family 1 member B10 expression in the liver of 550 patients with chronic HCV infection was immunohistochemically assessed and quantified. A multivariate Cox model was used to estimate the hazard ratios (HRs) of AKR1B10 expression for HCC development, and the cumulative incidence of HCC was evaluated using the Kaplan-Meier method. RESULTS: Aldo-keto reductase family 1 member B10 expression in the patients ranged from 0% to 80%. During the median follow-up of 3.2 years, 43 of 550 patients developed HCC. Multivariate analysis demonstrated that high AKR1B10 expression (≥6%) was an independent risk factor for HCC (HR, 6.43; 95% confidence interval, 2.90-14.25; P < 0.001). The 5-year cumulative incidences of HCC were 22.8% and 2.2% in patients with high and low AKR1B10 expression, respectively (P < 0.001). In subgroup analyses, the effects of high AKR1B10 expression on HCC development risk were significant over strata. In particular, HRs attributed to high AKR1B10 expression were significant in the subgroups that had been considered at a lower risk of HCC, such as in patients with younger age and mild hepatic fibrosis or those who achieved sustained virological response after interferon therapy. CONCLUSION: Various degrees of AKR1B10 upregulation in the liver were observed in patients with chronic HCV infection, and high AKR1B10 expression could be a novel predictor of HCC.

Stomagen positively regulates stomatal density in Arabidopsis.

Stomata in the epidermal tissues of leaves are valves through which passes CO(2), and as such they influence the global carbon cycle. The two-dimensional pattern and density of stomata in the leaf epidermis are genetically and environmentally regulated to optimize gas exchange. Two putative intercellular signalling factors, EPF1 and EPF2, function as negative regulators of stomatal development in Arabidopsis, possibly by interacting with the receptor-like protein TMM. One or more positive intercellular signalling factors are assumed to be involved in stomatal development, but their identities are unknown. Here we show that a novel secretory peptide, which we designate as stomagen, is a positive intercellular signalling factor that is conserved among vascular plants. Stomagen is a 45-amino-rich peptide that is generated from a 102-amino-acid precursor protein designated as STOMAGEN. Both an in planta analysis and a semi-in-vitro analysis with recombinant and chemically synthesized stomagen peptides showed that stomagen has stomata-inducing activity in a dose-dependent manner. A genetic analysis showed that TMM is epistatic to STOMAGEN (At4g12970), suggesting that stomatal development is finely regulated by competitive binding of positive and negative regulators to the same receptor. Notably, STOMAGEN is expressed in inner tissues (the mesophyll) of immature leaves but not in the epidermal tissues where stomata develop. This study provides evidence of a mesophyll-derived positive regulator of stomatal density. Our findings provide a conceptual advancement in understanding stomatal development: inner photosynthetic tissues optimize their function by regulating stomatal density in the epidermis for efficient uptake of CO(2).

Meeting report - oocyte maturation and fertilization: lessons from canonical and emerging models.

The EMBO workshop 'Oocyte maturation and fertilization: lessons from canonical and emerging models' was held at the Oceanologic Observatory of Banyuls in France in June 2013 and was organized by Anne-Marie Geneviere, Olivier Haccard, Peter Lenart and Alex McDougall. A total of 78 participants shared their research on germline formation, oocyte development, sperm, fertilization and early development. Here, we report the highlights of this meeting.