BackgroundN6-methyladenosine (m6A) is an important epitranscriptomic mark with high abundance in the brain. Recently, it has been found to be involved in the regulation of memory formation and mammalian cortical neurogenesis. However, while it is now established that m6A methylation occurs in a spatially restricted manner, its functions in specific brain regions still await elucidation.ResultsWe identify widespread and dynamic RNA m6A methylation in the developing mouse cerebellum and further uncover distinct features of continuous and temporal-specific m6A methylation across the four postnatal developmental processes. Temporal-specific m6A peaks from P7 to P60 exhibit remarkable changes in their distribution patterns along the mRNA transcripts. We also show spatiotemporal-specific expression of m6A writers METTL3, METTL14, and WTAP and erasers ALKBH5 and FTO in the mouse cerebellum. Ectopic expression of METTL3 mediated by lentivirus infection leads to disorganized structure of both Purkinje and glial cells. In addition, under hypobaric hypoxia exposure, Alkbh5-deletion causes abnormal cell proliferation and differentiation in the cerebellum through disturbing the balance of RNA m6A methylation in different cell fate determination genes. Notably, nuclear export of the hypermethylated RNAs is enhanced in the cerebellum of Alkbh5-deficient mice exposed to hypobaric hypoxia.ConclusionsTogether, our findings provide strong evidence that RNA m6A methylation is controlled in a precise spatiotemporal manner and participates in the regulation of postnatal development of the mouse cerebellum.Electronic supplementary materialThe online version of this article (10.1186/s13059-018-1435-z) contains supplementary material, which is available to authorized users.

N6-methyladenosine (m6A) is the most abundant epitranscriptomic mark found on mRNA and has important roles in various physiological processes. Despite the relatively high m6A levels in the brain, its potential functions in the brain remain largely unexplored. We performed a transcriptome-wide methylation analysis using the mouse brain to depict its region-specific methylation profile. RNA methylation levels in mouse cerebellum are generally higher than those in the cerebral cortex. Heterogeneity of RNA methylation exists across different brain regions and different types of neural cells including the mRNAs to be methylated, their methylation levels and methylation site selection. Common and region-specific methylation have different preferences for methylation site selection and thereby different impacts on their biological functions. In addition, high methylation levels of fragile X mental retardation protein (FMRP) target mRNAs suggest that m6A methylation is likely to be used for selective recognition of target mRNAs by FMRP in the synapse. Overall, we provide a region-specific map of RNA m6A methylation and characterize the distinct features of specific and common methylation in mouse cerebellum and cerebral cortex. Our results imply that RNA m6A methylation is a newly identified element in the region-specific gene regulatory network in the mouse brain.

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Chuzu Temple is one of the buildings in the historical architectural complex in “The Center of Heaven and Earth” in Dengfeng County. It is more than 800 years old. Currently, various kinds of damage can be found in the Chuzu Temple main hall. For more applicable conservation and renovation of the building, the status of the dougong (斗拱) under the external eaves of the Chuzu Temple main hall was investigated. Additionally, the existing types of damage and their causes were statistically analyzed to provide a practical reference for structural performance evaluations and protection reinforcement of the extant structure. According to the investigation results, 50.8% of the dougong members under the external eaves of the main hall had different types of damage. The main types of damage included detachment, plucking, holes, cracking, crushing, separation, and missing parts. The main causes were mechanical damage, bioerosion, and material degradation. Additionally, the study revealed that Larix sp., Ulmus sp., Quercus sp., and Populus sp. were the wood species used in the restoration to replace the antiquated wood.

Glandularia tenera (syn. Verbena tenera) is an herbaceous perennial ornamental plant used in gardens as an edging plant with beautiful white, red, or purple flowers. In autumn 2020 and 2021, severe powdery mildew infection was observed on G. tenera cultivar Xianghe in Renming Botanical garden in Shangqiu, Henan province, China (34.4568° N, 115.6640° E). Approximately 80% of leaves on each plant were symptomatic, and about 90% of the plants were infected. Powdery mildew colonies appeared as white spots on the adaxial surface of the leaves and stems of the plants in the initial infection stage. Later, mycelial growth was amphigenous, thick, forming irregular white patches, and effused to cover the whole leaf surface. Finally, leaves turned yellow and senescence occurred. Samples of symptomatic leaves were stained with trypan blue and examined under a Leica DM2500 microscope. Microscopic observations showed that conidia on infected leaves were hyaline and ellipsoid to oval with fibrosin bodies, measured 25 to 37 × 14 to 23 μm with a length/width ratio of 1.4 to 2.0. Conidiophores were unbranched, straight, 80 to 210× 10 to 14 µm in size, and produced two to five immature conidia in chains. Foot cells of conidiophores were cylindrical with slight constrictions at basal septa, and followed by one to three short cells. Fungal hyphae were septate, branched, and flexuous to straight and 4 to 7µm wide with indistinct to slightly nipple-shaped appressoria. Chasmothecia were not observed. These morphological characteristics were identical with the previous description of Podosphaera xanthii (Castagne) U. Braun & Shishkoff (Braun and Cook 2012). To confirm the identification, the sequence of ITS1-5.8s-ITS2 region of rDNA for the isolate SQVT was amplified from conidia collected from infected leaves with universal primers ITS1 and ITS4, sequenced and analyzed using the BLASTn search of GenBank. Amplicon was 565 bp (OM293967) and showed 99.82% similarity with sequence of P. xanthii from Eclipta prostrate (MT260063) in China (Xu et al. 2020), from Youngia denticulate (AB040351) in Japan (Hirata et al. 2000), and 99.65% with sequence of P. xanthii from V. brasiliensis in Korea (Cho et al. 2014). The domains D1 and D2 of the 28S rDNA for the isolate SQVTPX-1 was amplified with primer NL1/NL4. Amplicon was 613 bp (ON259308) and showed 100% similarity with sequence of P. xanthii from V. brasiliensis (AB936277) (Meeboon and Takamatsu, 2015). Pathogenicity tests were conducted by gently pressing the infected leaves onto leaves of five healthy G. tenera cultivar Xianghe plants. Five non-inoculated plants served as controls. Plants were maintained in a greenhouse at 25 ± 2°C. Eight days after inoculation, symptoms similar to those observed under natural conditions developed on the inoculated leaves of G. tenera plants, whereas the control plants remained symptomless. The fungus on inoculated leaves was morphologically identical to that first observed in the field. P. xanthii is a cosmopolitan powdery mildew fungus, parasitic on numerous plant species, especially Cucurbitaceae and Compositae plants. The pathogen has been reported infecting V. bonariensis (Hong et al. 2021), V. × hybrida in China (Zhuang 2005), and V. brasiliensis in Korea (Cho et al. 2014). Interestingly, G. tenera plants infected by P. xanthii were adjacent with V. × hybrida plants infected by P. xanthii in Renming Botanical garden. Incidence of P. xanthii on G. tenera add information on pathogen’s host range and help us develop comprehensive survey and effective management of the disease. To our knowledge, this is the first report of P. xanthii on G. tenera in China (Farr and Rossman 2021). Braun, U., and Cook, R. T. A. 2012. Taxonomic Manual of the Erysiphales (Powdery Mildews). CBS Biodiversity Series No. 11. CBS, Utrecht, the Netherlands. Cho, S. E., et al. 2014. Plant Dis. 98: 1159. Farr, D. F., and Rossman, A. Y. 2021. Fungal Databases, Syst. Mycol. Microbiol. Lab., ARS, USDA. Hong, Q. Q., et al. 2021. Plant Dis. 105: 3297. Hirata, T., et al. 2000. Can. J. Bot. 78: 1521-1530. Meeboon, J. and Takamatsu, S. 2015. Mycoscience . 56: 243-251. Xu, D. D., et al. 2020. Plant Dis. 104: 3263. Zhuang, W. Y. 2005. Fungi of northwestern China. Mycotaxon, Ltd., Ithaca, NY.