Human iPSC Glial Mouse Chimeras Reveal Glial Contributions to Schizophrenia

In this study, we investigated whether intrinsic glial dysfunction contributes to the pathogenesis of schizophrenia (SCZ). Our approach was to establish humanized glial chimeric mice using glial progenitor cells (GPCs) produced from induced pluripotent stem cells derived from patients with childhood-onset SCZ. After neonatal implantation into myelin-deficient shiverer mice, SCZ GPCs showed premature migration into the cortex, leading to reduced white matter expansion and hypomyelination relative to controls. The SCZ glial chimeras also showed delayed astrocytic differentiation and abnormal astrocytic morphologies. When established in myelin wild-type hosts, SCZ glial mice showed reduced prepulse inhibition and abnormal behavior, including excessive anxiety, antisocial traits, and disturbed sleep. RNA-seq of cultured SCZ human glial progenitor cells (hGPCs) revealed disrupted glial differentiation-associated and synaptic gene expression, indicating that glial pathology was cell autonomous. Our data therefore suggest a causal role for impaired glial maturation in the development of schizophrenia and provide a humanized model for its in vivo assessment.

The effect of maternal photoperiod on seasonal dormancy in Arabidopsis thaliana (Brassicaceae)

The maternal photoperiod at the time of seed maturation can predict the seasonal conditions of newly dispersed seeds. We investigated the effects of maternal photoperiod on seasonal dormancy in Arabidopsis thaliana using a set of F6 recombinant inbred lines derived from a cross between individuals from two natural populations (Cal-0 and Tac-0) differing in cold requirements for germination. We grew 40 Cal × Tac lines in a long-day photoperiod (8 h of full spectrum light plus 8 h of low-fluence incandescent light) and a short-day photoperiod (8 h full spectrum light). We then exposed seeds from each family and maternal photoperiod to either a cold stratification treatment (4°C, 21 d) or no cold stratification. Both maternal photoperiod and progeny stratification influenced the percentage of seeds that germinated and the speed of germination. The short-day photoperiod caused increased responsiveness to stratification, with higher germination percentages and speeds in stratified seeds. Stratification influenced the expression of maternal photoperiod effects, such that short days increased germination percentage and speed in stratified seeds but inhibited germination in unstratified seeds. Families differed significantly in their plasticity to maternal photoperiod and stratification, but genetic variation for plasticity to maternal photoperiod was expressed only in unstratified seeds. Because the expression of maternal photoperiod effects and genetic variation for photoperiod effects depended on progeny stratification, the evolution of these maternal effects will depend on the seasonal environment experienced by progeny.

Efficient directional cloning of recombinant adenovirus vectors using DNA-protein complex

We describe an efficient cloning system utilizing adenoviral DNA-protein complexes which allows the directional cloning of genes into adenoviral expression vectors in a single step. DNA-protein complexes derived from a recombinant adenovirus (AVC2.null) were isolated by sequential use of CsCl step gradients followed by isopycnic centrifugation in a mixture of CsCl and guanidine HCl. AVC2.null is an adenoviral expression vector containing unique restriction sites between the human CMV-IE promoter and the SV40 intron/polyadenylation site. Transgenes were prepared for cloning into this vector by introduction of compatible restriction sites by PCR. A vector expressing rat granulocyte-macrophage colony-stimulating factor (GM-CSF) was constructed using DNA-protein complex as well as by traditional recombination techniques. The efficacy of our adenoviral cloning system utilizing DNA-protein complex was two logs higher than that seen using homologous recombination. All viruses generated by directional ligation of the insert into the vector DNA-protein complexes contained the desired transgene in the correct orientation. This technique greatly simplifies and accelerates the generation of recombinant adenoviral vectors.