Uncovering the Functional Link Between SHANK3 Deletions and Deficiency in Neurodevelopment Using iPSC-Derived Human Neurons

SHANK3 mutations, including de novo deletions, have been associated with autism spectrum disorders (ASD). However, the effects of SHANK3 loss of function on neurodevelopment remain poorly understood. Here we generated human induced pluripotent stem cells (iPSC) in vitro, followed by neuro-differentiation and lentivirus-mediated shRNA expression to evaluate how SHANK3 knockdown affects the in vitro neurodevelopmental process at multiple time points (up to 4 weeks). We found that SHANK3 knockdown impaired both early stage of neuronal development and mature neuronal function, as demonstrated by a reduction in neuronal soma size, growth cone area, neurite length and branch numbers. Notably, electrophysiology analyses showed defects in excitatory and inhibitory synaptic transmission. Furthermore, transcriptome analyses revealed that multiple biological pathways related to neuron projection, motility and regulation of neurogenesis were disrupted in cells with SHANK3 knockdown. In conclusion, utilizing a human iPSC-based neural induction model, this study presented combined morphological, electrophysiological and transcription evidence that support that SHANK3 as an intrinsic, cell autonomous factor that controls cellular function development in human neurons

Stand Characteristics Rather than Soil Properties Contribute More to the Expansion of Moso Bamboo (<i>Phyllostachys edulis</i>) into Its Neighboring Forests in Subtropical Region

Moso bamboo (Phyllostachys edulis), once highly praised worldwide, has been found to be a problematic species due to its unconstrained expansion into adjacent woodlands and negative effects on the function services of forest ecosystems. To determine the major factors affecting bamboo expansion into neighbor woodlands, we investigated the expansion characteristics of moso bamboo and the properties of stand structure and soil for 58 bamboo–woodland interfaces (BWIs) across Jiangxi province in China. Then, we analyzed the relationships between the variables of bamboo expansion and the properties of interfaces through a redundancy analysis. The characteristics (the expansion distance and the number and size of new culms) of moso bamboo expansion into disturbed forests were more significant (p < 0.01) than those into non-disturbed forests. The bamboo expansion into deciduous broad-leaved forest was much faster (1.33 m/yr) than evergreen broad-leaved forest (0.82 m/yr) and needle-leaved forest (1.08 m/yr). The characteristics of stand structure had more direct explanatory power (58.8%) than soil properties (4.3%) and their interaction (10.0%) for the variations in bamboo expansion. The canopy closure of recipient forests was identified as the most significant factor negatively correlated to bamboo expansion. The number of parent culms and the ratio of deciduous to evergreen trees ranked in sequence, and both imposed positive effects on the expansion. Regarding soil properties, only the water content was identified for its explanatory power and negative influence on bamboo expansion. Our findings illustrated that the expansion of moso bamboo showed remarkable variations when facing different woodlands. Stand characteristics (canopy closure, canopy height, etc.) of good explanatory power were the major variables affecting the expansion of moso bamboo. In order to control the expansion of bamboo and protect woodlands, disturbances (extracting timber, girdling trunks) should be prevented in bamboo–woodland interfaces

Stand Characteristics Rather than Soil Properties Contribute More to the Expansion of Moso Bamboo (Phyllostachys edulis) into Its Neighboring Forests in Subtropical Region

Moso bamboo (Phyllostachys edulis), once highly praised worldwide, has been found to be a problematic species due to its unconstrained expansion into adjacent woodlands and negative effects on the function services of forest ecosystems. To determine the major factors affecting bamboo expansion into neighbor woodlands, we investigated the expansion characteristics of moso bamboo and the properties of stand structure and soil for 58 bamboo&ndash;woodland interfaces (BWIs) across Jiangxi province in China. Then, we analyzed the relationships between the variables of bamboo expansion and the properties of interfaces through a redundancy analysis. The characteristics (the expansion distance and the number and size of new culms) of moso bamboo expansion into disturbed forests were more significant (p &lt; 0.01) than those into non-disturbed forests. The bamboo expansion into deciduous broad-leaved forest was much faster (1.33 m/yr) than evergreen broad-leaved forest (0.82 m/yr) and needle-leaved forest (1.08 m/yr). The characteristics of stand structure had more direct explanatory power (58.8%) than soil properties (4.3%) and their interaction (10.0%) for the variations in bamboo expansion. The canopy closure of recipient forests was identified as the most significant factor negatively correlated to bamboo expansion. The number of parent culms and the ratio of deciduous to evergreen trees ranked in sequence, and both imposed positive effects on the expansion. Regarding soil properties, only the water content was identified for its explanatory power and negative influence on bamboo expansion. Our findings illustrated that the expansion of moso bamboo showed remarkable variations when facing different woodlands. Stand characteristics (canopy closure, canopy height, etc.) of good explanatory power were the major variables affecting the expansion of moso bamboo. In order to control the expansion of bamboo and protect woodlands, disturbances (extracting timber, girdling trunks) should be prevented in bamboo&ndash;woodland interfaces

Sperm cells are passive cargo of the pollen tube in plant fertilization

Sperm cells of seed plants have lost their motility and are transported by the vegetative pollen tube cell for fertilization, but the extent to which they regulate their own transportation is a long-standing debate. Here we show that Arabidopsis lacking two bHLH transcription factors produces pollen without sperm cells. This abnormal pollen mostly behaves like the wild type and demonstrates that sperm cells are dispensable for normal pollen tube development

CFLAP1 and CFLAP2 Are Two bHLH Transcription Factors Participating in Synergistic Regulation of AtCFL1-Mediated Cuticle Development in Arabidopsis

The cuticle is a hydrophobic lipid layer covering the epidermal cells of terrestrial plants. Although many genes involved in Arabidopsis cuticle development have been identified, the transcriptional regulation of these genes is largely unknown. Previously, we demonstrated that AtCFL1 negatively regulates cuticle development by interacting with the HD-ZIP IV transcription factor HDG1. Here, we report that two bHLH transcription factors, AtCFL1 associated protein 1 (CFLAP1) and CFLAP2, are also involved in AtCFL1-mediated regulation of cuticle development. CFLAP1 and CFLAP2 interact with AtCFL1 both in vitro and in vivo. Overexpression of either CFLAP1 or CFLAP2 led to expressional changes of genes involved in fatty acids, cutin and wax biosynthesis pathways and caused multiple cuticle defective phenotypes such as organ fusion, breakage of the cuticle layer and decreased epicuticular wax crystal loading. Functional inactivation of CFLAP1 and CFLAP2 by chimeric repression technology caused opposite phenotypes to the CFLAP1 overexpressor plants. Interestingly, we find that, similar to the transcription factor HDG1, the function of CFLAP1 in cuticle development is dependent on the presence of AtCFL1. Furthermore, both HDG1 and CFLAP1/2 interact with the same C-terminal C4 zinc finger domain of AtCFL1, a domain that is essential for AtCFL1 function. These results suggest that AtCFL1 may serve as a master regulator in the transcriptional regulation of cuticle development, and that CFLAP1 and CFLAP2 are involved in the AtCFL1-mediated regulation pathway, probably through competing with HDG1 to bind to AtCFL1

Maternal ENODLs Are Required for Pollen Tube Reception in Arabidopsis

During the angiosperm (flowering-plant) life cycle, double fertilization represents the hallmark between diploid and haploid generations [1]. The success of double fertilization largely depends on compatible communication between the male gametophyte (pollen tube) and the maternal tissues of the flower, culminating in precise pollen tube guidance to the female gametophyte (embryo sac) and its rupture to release sperm cells. Several important factors involved in the pollen tube reception have been identified recently [2-6], but the underlying signaling pathways are far from being understood. Here, we report that a group of female-specific small proteins, early nodulin-like proteins (ENODLs, or ENs), are required for pollen tube reception. ENs are featured with a plastocyanin-like (PCNL) domain, an arabinogalactan (AG) glycomodule, and a predicted glycosylphosphatidylinositol (GPI) anchor motif. We show that ENs are asymmetrically distributed at the plasma membrane of the synergid cells and accumulate at the filiform apparatus, where arriving pollen tubes communicate with the embryo sac. EN14 strongly and specifically interacts with the extracellular domain of the receptor-like kinase FERONIA, localized at the synergid cell surface and known to critically control pollen tube reception [6]. Wild-type pollen tubes failed to arrest growth and to rupture after entering the ovules of quintuple loss-of-function EN mutants, indicating a central role of ENs in male-female communication and pollen tube reception. Moreover, overexpression of EN15 by the endogenous promoter caused disturbed pollen tube guidance and reduced fertility. These data suggest that female-derived GPI-anchored ENODLs play an essential role in male-female communication and fertilization.Natural Science Foundation of China [31230006, 31370344]; National Basic Research Program of China [2012CB944801]; German Research Council (DFG Collaborative Research Center) [SFB924]SCI(E)[email protected]

Cysteine-rich peptides promote interspecific genetic isolation in Arabidopsis

Reproductive isolation is a prerequisite for speciation. Failure of communication between female tissues of the pistil and paternal pollen tubes imposes hybridization barriers in flowering plants. Arabidopsis thaliana LURE1 (AtLURE1) peptides and their male receptor PRK6 aid attraction of the growing pollen tube to the ovule. Here, we report that the knockout of the entire AtLURE1 gene family did not affect fertility, indicating that AtLURE1-PRK6-mediated signaling is not required for successful fertilization within one Arabidopsis species. AtLURE1s instead function as pollen tube emergence accelerators that favor conspecific pollen over pollen from other species and thus promote reproductive isolation. We also identified maternal peptides XIUQIU1 to -4, which attract pollen tubes regardless of species. Cooperation between ovule attraction and pollen tube growth acceleration favors conspecific fertilization and promotes reproductive isolation