Auriculocondylar syndrome 2 results from the dominant-negative action of PLCB4 variants.

Auriculocondylar syndrome 2 (ARCND2) is a rare autosomal dominant craniofacial malformation syndrome linked to multiple genetic variants in the coding sequence of phospholipase C β4 (PLCB4). PLCB4 is a direct signaling effector of the endothelin receptor type A (EDNRA)-Gq/11 pathway, which establishes the identity of neural crest cells (NCCs) that form lower jaw and middle ear structures. However, the functional consequences of PLCB4 variants on EDNRA signaling is not known. Here, we show, using multiple signaling reporter assays, that known PLCB4 variants resulting from missense mutations exert a dominant-negative interference over EDNRA signaling. In addition, using CRISPR/Cas9, we find that F0 mouse embryos modeling one PLCB4 variant have facial defects recapitulating those observed in hypomorphic Ednra mouse models, including a bone that we identify as an atavistic change in the posterior palate/oral cavity. Remarkably, we have identified a similar osseous phenotype in a child with ARCND2. Our results identify the disease mechanism of ARCND2, demonstrate that the PLCB4 variants cause craniofacial differences and illustrate how minor changes in signaling within NCCs may have driven evolutionary changes in jaw structure and function. This article has an associated First Person interview with the first author of the paper

Mouse Gestation Length Is Genetically Determined

Background: Preterm birth is an enormous public health problem, affecting over 12 % of live births and costing over $26 billion in the United States alone. The causes are complex, but twin studies support the role of genetics in determining gestation length. Despite widespread use of the mouse in studies of the genetics of preterm birth, there have been few studies that actually address the precise natural gestation length of the mouse, and to what degree the timing of labor and birth is genetically determined. Methodology/Principal Findings: To further develop the mouse as a genetic model of preterm birth, we developed a highthroughput monitoring system and measured the gestation length in 15 inbred strains. Our results show an unexpectedly wide variation in overall gestation length between strains that approaches two full days, while intra-strain variation is quite low. Although litter size shows a strong inverse correlation with gestation length, genetic difference alone accounts for a significant portion of the variation. In addition, ovarian transplant experiments support a primary role of maternal genetics in the determination of gestation length. Preliminary analysis of gestation length in the C57BL/6J-Chr # A/J /NaJ chromosome substitution strain (B.A CSS) panel suggests complex genetic control of gestation length. Conclusions/Significance: Together, these data support the role of genetics in regulating gestation length and present th

TMEM161B modulates radial glial scaffolding in neocortical development.

TMEM161B encodes an evolutionarily conserved widely expressed novel 8-pass trans- membrane protein of unknown function in human. Here we identify TMEM161B homozygous hypomorphic missense variants in our recessive polymicrogyria (PMG) cohort. Patients carrying TMEM161B mutations exhibit striking neocortical PMG and intellectual disability. Tmem161b knockout mice fail to develop midline hem- ispheric cleavage, whereas knock-in of patient mutations and patient-derived brain organoids show defects in apical cell polarity and radial glial scaffolding. We found that TMEM161B modulates actin filopodia, functioning upstream of the Rho-GTPase CDC42. Our data link TMEM161B with human PMG, likely regulating radial glia apical polarity during neocortical development

Crowdsourcing hypothesis tests: Making transparent how design choices shape research results

To what extent are research results influenced by subjective decisions that scientists make as they design studies? Fifteen research teams independently designed studies to answer fiveoriginal research questions related to moral judgments, negotiations, and implicit cognition. Participants from two separate large samples (total N > 15,000) were then randomly assigned to complete one version of each study. Effect sizes varied dramatically across different sets of materials designed to test the same hypothesis: materials from different teams renderedstatistically significant effects in opposite directions for four out of five hypotheses, with the narrowest range in estimates being d = -0.37 to +0.26. Meta-analysis and a Bayesian perspective on the results revealed overall support for two hypotheses, and a lack of support for three hypotheses. Overall, practically none of the variability in effect sizes was attributable to the skill of the research team in designing materials, while considerable variability was attributable to the hypothesis being tested. In a forecasting survey, predictions of other scientists were significantly correlated with study results, both across and within hypotheses. Crowdsourced testing of research hypotheses helps reveal the true consistency of empirical support for a scientific claim.</div

A novel allele of Alx4 results in reduced Fgf10 expression and failure of eyelid fusion in mice.

Normal fusion of developing eyelids requires coordination of inductive signals from the eyelid mesenchyme with migration of the periderm cell layer and constriction of the eyelids across the eye. Failure of this process results in an eyelids open at birth (EOB) phenotype in mice. We have identified a novel spontaneous allele of Alx4 that displays EOB, in addition to polydactyly and cranial malformations. Alx4 is expressed in the eyelid mesenchyme prior to and during eyelid fusion in a domain overlapping the expression of genes that also play a role in normal eyelid development. We show that Alx4 mutant mice have reduced expression of Fgf10, a key factor expressed in the mesenchyme that is required for initiation of eyelid fusion by the periderm. This is accompanied by a reduced number of periderm cells expressing phosphorylated c-Jun, consistent with the incomplete ablation of Fgf10 expression. Together, these data demonstrate that eyelid fusion in mice requires the expression of Alx4, accompanied by the loss of normal expression of essential components of the eyelid fusion pathway. Mamm Genome 2015 Apr; 26(3-4):173-8

Prevalence and correlates of heavy smoking and nicotine dependence in adolescents with bipolar and cannabis use disorders.

The study examined the prevalence and correlates of heavy smoking and nicotine dependence in adolescents with bipolar and cannabis use disorders. Participants were 80 adolescents between 13 and 22 years of age with co-occurring bipolar I disorder and cannabis abuse or dependence who reported ever trying a cigarette. Diagnostic and symptom severity measures were completed as part of the baseline assessments for a clinical trial. Almost half (49%) of these participants who ever tried a cigarette were current heavy smokers (≥10 cigarettes/day), and 70% met DSM-IV-TR lifetime criteria for nicotine dependence. Heavy smoking was associated with older age, heavier marijuana use and greater compulsive craving, lifetime diagnoses of attention-deficit/hyperactivity disorder, conduct disorder, illicit drug use disorders, and poorer overall functioning. Nicotine dependence was related to White race, higher current mania severity, and poorer overall functioning. These findings suggest that heavy smoking and nicotine dependence were highly prevalent among these adolescents. Although both were associated with greater physical and psychosocial problems, only heavy smoking was linked to a clear pattern of more severe substance-related and psychiatric problems. Further research to elucidate mechanisms and develop interventions to address early, entrenched patterns of co-use of tobacco and marijuana is warranted

Prevalence and correlates of heavy smoking and nicotine dependence in adolescents with bipolar and cannabis use disorders.

The study examined the prevalence and correlates of heavy smoking and nicotine dependence in adolescents with bipolar and cannabis use disorders. Participants were 80 adolescents between 13 and 22 years of age with co-occurring bipolar I disorder and cannabis abuse or dependence who reported ever trying a cigarette. Diagnostic and symptom severity measures were completed as part of the baseline assessments for a clinical trial. Almost half (49%) of these participants who ever tried a cigarette were current heavy smokers (≥10 cigarettes/day), and 70% met DSM-IV-TR lifetime criteria for nicotine dependence. Heavy smoking was associated with older age, heavier marijuana use and greater compulsive craving, lifetime diagnoses of attention-deficit/hyperactivity disorder, conduct disorder, illicit drug use disorders, and poorer overall functioning. Nicotine dependence was related to White race, higher current mania severity, and poorer overall functioning. These findings suggest that heavy smoking and nicotine dependence were highly prevalent among these adolescents. Although both were associated with greater physical and psychosocial problems, only heavy smoking was linked to a clear pattern of more severe substance-related and psychiatric problems. Further research to elucidate mechanisms and develop interventions to address early, entrenched patterns of co-use of tobacco and marijuana is warranted

Maternal Synchronization of Gestational Length and Lung Maturation

Among all mammals, fetal growth and organ maturation must be precisely synchronized with gestational length to optimize survival at birth. Lack of pulmonary maturation is the major cause of infant mortality in preterm birth. Whether fetal or maternal genotypes influence the close relationship between the length of gestation and lung function at birth is unknown. Structural and biochemical indicators of pulmonary maturity were measured in two mouse strains whose gestational length differed by one day. Shorter gestation in C57BL/6J mice was associated with advanced morphological and biochemical pulmonary development and better perinatal survival when compared to A/J pups born prematurely. After ovarian transplantation, A/J pups were born early in C57BL/6J dams and survived after birth, consistent with maternal control gestational length. Expression of genes critical for perinatal lung function was assessed in A/J pups born after ovarian transfer. A subset of mRNAs important for perinatal respiratory adaptation was selectively induced in the A/J pups born after ovarian transfer. mRNAs precociously induced after ovarian transfer indicated an important role for the transcription factors C/EBPa and CREB in maternally induced lung maturation. We conclude that fetal lung maturation is determined by both fetal and maternal genotypes. Ovarian transfer experiments demonstrated that maternal genotyp