Interneuron origin and molecular diversity in the human fetal brain.

Precise generation of excitatory neurons and inhibitory interneurons is crucial for proper formation and function of neural circuits in the mammalian brain. Because of the size and complexity of the human brain, it is a challenge to reveal the rich diversity of interneurons. To decipher origin and diversity of interneurons in the human fetal subpallium, here we show molecular features of diverse subtypes of interneuron progenitors and precursors by conducting single-cell RNA sequencing and in situ sequencing. Interneuron precursors in the medial and lateral ganglionic eminence simultaneously procure temporal and spatial identity through expressing a combination of specific sets of RNA transcripts. Acquisition of various interneuron subtypes in adult human brains occurs even at fetal stages. Our study uncovers complex molecular signatures of interneuron progenitors and precursors in the human fetal subpallium and highlights the logic and programs in the origin and lineage specification of various interneurons.

Prenatal stress leads to deficits in brain development, mood related behaviors and gut microbiota in offspring.

Early exposure to stressful and adverse life events at fetal and neonatal stages is one of crucial risk factors for mood disorders such as anxiety and depressive disorder in adulthood. Intergenerational effects of prenatal stress on offspring are still not fully understood. We here uncover a significant negative impact of prenatal stress on brain development in embryos and newborns, and on mood-related behaviors and gut microbiota in adult offspring. Prenatal stress leads to reduced numbers in neural progenitors and newborn neurons, and altered gene expression profiles in the mouse embryonic cerebral cortex. Adult mouse offspring exposed to prenatal stress displays altered gene expression in the cortex and elevated responses in anxiety- and depression-like behaviors. Interestingly, prenatal stress has an enduring effect on gut microbiota, as specific microbial community structure is altered in adult F1 offspring treated with prenatal stress, compared to that of the control. Our results highlight the essential impact of prenatal stress on cortical neurogenesis, gene expression patterns, mood-related behaviors, and even gut microbiota in the next generation.

A hydrophobin gene, Hyd9, plays an important role in the formation of aerial hyphae and primordia in Flammulina filiformis.

Flammulina filiformis is an edible fungus that is largely cultivated and widely consumed around the world. The quantity and quality of the primordia, which gives rise to the fruiting body, affects its production efficiency. Hydrophobins are involved in the formation of the fruiting body of macrofungi. However, functional verification of the hydrophobin genes is limited to date. In this study, we used gene silencing and overexpression analyses to investigate the function of one F. filiformis hydrophobin gene (Hyd9) during the development of the fruiting body. The Hyd9-silenced transformants exhibited sparse aerial hyphae, resulting in fewer primordia and fruiting bodies. In contrast, the Hyd9 overexpression strain displayed denser aerial hyphae and more primordia. The phenotypes of these transgenic lines strongly suggested that Hyd9 plays an important role in the formation of aerial hyphal knots (the primary stage of primordia) and primordia in F. filiformis. These results will be beneficial for developing more efficient methods to induce primordia formation in F. filiformis and other commercially valuable mushrooms.

A Jacalin-Related Lectin Regulated the Formation of Aerial Mycelium and Fruiting Body in Flammulina velutipes.

Flammulina velutipes, one of the most popular mushroom species in the world, has been recognized as a useful model system to study the biochemical and physiological aspects of the formation and elongation of fruit body. However, few reports have been published on the regulation of fruiting body formation in F. velutipes at the molecular level. In this study, a jacalin-related lectin gene from F. velutipes was characterized. The phylogenetic tree revealed that Fv-JRL1 clustered with other basidiomycete jacalin-like lectins. Moreover, the transcriptional pattern of the Fv-JRL1 gene in different developmental stages of F. velutipes implied that Fv-JRL1 could be important for formation of fruit body. Additionally, RNA interference (RNAi) and overexpression analyses provided powerful evidence that the lectin gene Fv-JRL1 from F. velutipes plays important roles in fruiting body formation.

The Sequence Characteristics and Expression Models Reveal Superoxide Dismutase Involved in Cold Response and Fruiting Body Development in Volvariella volvacea.

As the first defence for cells to counteract the toxicity of active oxygen, superoxide dismutase (SOD) plays an important role in the response of living organisms to stress and cell differentiation. One extracellular Cu-ZnSOD (ecCu-ZnSOD), and two MnSODs, were identified based on the Volvariella volvacea genome sequence. All three genes have complicated alternative splicing modes during transcription; only when the fourth intron is retained can the Vv_Cu-Znsod1 gene be translated into a protein sequence with SOD functional domains. The expression levels of the three sod genes in the pilei are higher than in the stipe. The Vv_Cu-Znsod1 and the Vv_Mnsod2 are co-expressed in different developmental stages of the fruiting body, with the highest level of expression in the pilei of the egg stage, and they show a significant, positive correlation with the efficiency of karyogamy, indicating the potential role of these two genes during karyogamy. The expression of the ecCu-Znsod and two Vv_Mnsod genes showed a significant up-regulated when treated by cold stress for one hour; however, the lack of the intracellular Cu-ZnSOD encoding gene (icCu-Znsod) and the special locus of the ecCu-Znsod gene initiation codon suggested a possible reason for the autolysis phenomenon of V. volvacea in cold conditions.

The multigene family of fungal laccases and their expression in the white rot basidiomycete Flammulina velutipes.

Fungal laccases play important roles in matrix degradation. Eleven laccase genes, including three novel ones (designated lac1, lac2 and lac4) were identified after sequencing the entire genome of the edible, white-rot fungus Flammulina velutipes. Analysis using bioinformatics revealed that all of the laccases, except lac3, possess a signal peptide. These laccase proteins consist of 502-670 amino acids and have predicted molecular weights ranging from 55kDa to 74kDa. These proteins each contain four copper-binding sites, except for Lac10. Transcriptomes were sequenced at different developmental stages and in different fruiting body tissues to analyze if there was differential expression of laccase genes. The novel laccase gene lac4 exhibited the highest expression levels among all of the observed laccases at every developmental stage and in all fruiting body tissues examined. We conclude that laccases in F. velutipes play a role not only in lignin degradation, but also in fruiting body formation and development.