A Plant Germline-Specific Integrator of Sperm Specification and Cell Cycle Progression

The unique double fertilisation mechanism in flowering plants depends upon a pair of functional sperm cells. During male gametogenesis, each haploid microspore undergoes an asymmetric division to produce a large, non-germline vegetative cell and a single germ cell that divides once to produce the sperm cell pair. Despite the importance of sperm cells in plant reproduction, relatively little is known about the molecular mechanisms controlling germ cell proliferation and specification. Here, we investigate the role of the Arabidopsis male germline-specific Myb protein DUO POLLEN1, DUO1, as a positive regulator of male germline development. We show that DUO1 is required for correct male germ cell differentiation including the expression of key genes required for fertilisation. DUO1 is also necessary for male germ cell division, and we show that DUO1 is required for the germline expression of the G2/M regulator AtCycB1;1 and that AtCycB1:1 can partially rescue defective germ cell division in duo1. We further show that the male germline-restricted expression of DUO1 depends upon positive promoter elements and not upon a proposed repressor binding site. Thus, DUO1 is a key regulator in the production of functional sperm cells in flowering plants that has a novel integrative role linking gametic cell specification and cell cycle progression

Arabidopsis DUO POLLEN3 Is a Key Regulator of Male Germline Development and Embryogenesis

Male germline development in angiosperms produces the pair of sperm cells required for double fertilization. A key regulator of this process in Arabidopsis thaliana is the male germline-specific transcription factor DUO POLLEN1 (DUO1) that coordinates germ cell division and gamete specification. Here, we uncover the role of DUO3, a nuclear protein that has a distinct, but overlapping role with DUO1 in male germline development. DUO3 is a conserved protein in land plants and is related to GON-4, a cell lineage regulator of gonadogenesis in Caenorhabditis elegans. Mutant duo3-1 germ cells either fail to divide or show a delay in division, and we show that, unlike DUO1, DUO3 promotes entry into mitosis independent of the G2/M regulator CYCB1;1. We also show that DUO3 is required for the expression of a subset of germline genes under DUO1 control and that like DUO1, DUO3 is essential for sperm cell specification and fertilization. Furthermore, we demonstrate an essential sporophytic role for DUO3 in cell division and embryo patterning. Our findings demonstrate essential developmental roles for DUO3 in cell cycle progression and cell specification in both gametophytic and sporophytic tissues

Imprinting of the Polycomb Group Gene MEDEA Serves as a Ploidy Sensor in Arabidopsis

Balanced maternal and paternal genome contributions are a requirement for successful seed development. Unbalanced contributions often cause seed abortion, a phenomenon that has been termed “triploid block.” Misregulation of imprinted regulatory genes has been proposed to be the underlying cause for abnormalities in growth and structure of the endosperm in seeds with deviating parental contributions. We identified a mutant forming unreduced pollen that enabled us to investigate direct effects of unbalanced parental genome contributions on seed development and to reveal the underlying molecular mechanism of dosage sensitivity. We provide evidence that parent-of-origin–specific expression of the Polycomb group (PcG) gene MEDEA is causally responsible for seed developmental aberrations in Arabidopsis seeds with increased paternal genome contributions. We propose that imprinted expression of PcG genes is an evolutionary conserved mechanism to balance parental genome contributions in embryo nourishing tissues

Housing supply and brownfield regeneration in a post-Barker review world: A comparison of policy and practice in England and Scotland

The findings of the Barker review, which examined the reasons for the undersupply of UK housing, have important implications for the devolved constituents of the UK, including Scotland. This paper traces the emergence of the brownfield regeneration policy agenda across the UK and examines how the Barker review connects with this brownfield policy focus. The paper compares housing and brownfield policies and practices in England and Scotland, places them in an international context and elicits wider lessons for devolved governance in relation to housing policy, in terms of `centrist—local' tensions. Estimates based on published data suggest that Barker's emphasis on increased housing supply cannot easily be reconciled with the current emphasis on brownfield development and is likely to require a return to greenfield development in both countries

Socioeconomic deprivation is associated with reduced response and lower treatment persistence with TNF inhibitors in rheumatoid arthritis

Objective To investigate the association between socioeconomic deprivation and outcomes following TNF inhibitor (TNFi) treatment. Methods Individuals commencing their first TNFi in the British Society for Rheumatology Biologics Register for RA (BSRBR-RA) and Biologics in RA Genetics and Genomics Study Syndicate (BRAGGSS) cohort were included. Socioeconomic deprivation was proxied using the Index of Multiple Deprivation and categorized as 20% most deprived, middle 40% or 40% least deprived. DAS28-derived outcomes at 6 months (BSRBR-RA) and 3 months (BRAGGSS) were compared using regression models with the least deprived as referent. Risks of all-cause and cause-specific drug discontinuation were compared using Cox models in the BSRBR-RA. Additional analyses adjusted for lifestyle factors (e.g. smoking, BMI) as potential mediators. Results 16 085 individuals in the BSRBR-RA were included (mean age 56 years, 76% female), of whom 18%, 41% and 41% were in the most, middle and least deprived groups, respectively. Of 3459 included in BRAGGSS (mean age 57, 77% female), proportions were 22%, 36% and 41%, respectively. The most deprived group had 0.3-unit higher 6-month DAS28 (95% CI 0.22, 0.37) and were less likely to achieve low disease activity (odds ratio [OR] 0.76; 95% CI 0.68, 0.84) in unadjusted models. Results were similar for 3-month DAS28 (β = 0.23; 95% CI 0.11, 0.36) and low disease activity (OR 0.77; 95% CI 0.63, 0.94). The most deprived were more likely to discontinue treatment (hazard ratio 1.18; 95% CI 1.12, 1.25), driven by ineffectiveness rather than adverse events. Adjusted estimates were generally attenuated. Conclusion Socioeconomic deprivation is associated with reduced response to TNFi. Improvements in determinants of health other than lifestyle factors are needed to address socioeconomic inequities

SOCIAL CLASS AND VIOLENT BEHAVIOR (DELINQUENCY).

The purpose of this study is to specify more precisely the relationship between social class and crime or delinquency by focusing on a particular offense, violent behavior. Police records and survey data from four studies are analyzed. These data sets are derived from samples from around the United States and span nearly a twenty-year period. The empirical analysis begins by examining the relationship between parental status and violent behavior. One of the principal conclusions drawn from this analysis is that the magnitude of the relationship between social class and violent behavior is contingent upon the way class or status is defined or measured. Depending upon the way class is operationalized, its relationship with violent behavior is nonexistent, moderate, or relatively strong. To account for this social distribution of violent behavior, four major theories of crime and delinquency are tested. Structural and cultural theories in general fail to provide an adequate explanation. For example, consistent with research on general delinquent behavior, there is almost no support for the propositions of strain theory. In contrast, processual and psychological theories of crime and delinquency receive considerable support. Social learning theory measures of imitation are among the strongest correlates of violent behavior. In one data set, imitation measures completely account for the class distribution of violence. Social control theory measures, such as attachment to others, are also strongly correlated with violent behavior. A series of crucial experiments comparing control theory propositions with predictions of other theories yield results more consistent with control theory. The relationship between adolescent status and violent behavior is also examined. Parallel to the analysis of parental status, the results vary depending on the measure of adolescent status used. These results suggest that there are distinct dimensions of adolescent status which must be assessed separately