Biology subjects

Mao, J.

Publications and source records attributed to Mao, J..

4 recordsLinked to original sources

bioRxiv2018

Cyclin B3 is specifically required for metaphase to anaphase transition in mouse oocyte meiosis I

Meiosis, a cell division to generate gametes for sexual reproduction in eukaryotes, executes a single round of DNA replication and two successive rounds of chromosome segregation [1]. The extraordinary reliability of the meiotic cycle requires the activities of cyclin-dependent kinases (Cdks) associated with specific cyclins [2-4]. Cyclins are the regulatory subunits of protein kinases, which are the main regulators of maturation promoting factor or mitosis promoting factor (MPF) [5, 6] and anaphase-promoting complex/cyclosome (APC/C) [7, 8] in eukaryotic cell division. But how cyclins collaborate to control meiosis is still largely unknown. Cyclin B3 (Ccnb3) shares homology with A- and B-type cyclins [9], and is conserved during higher eukaryote evolution [10-17]. Previous studies have shown that Ccnb3-deleted females are sterile with oocytes unable to complete meiosis I in Drosophila [18], implying that Ccnb3 may have a special role in meiosis. To clarify the function of Ccnb3 in meiosis in mammalian species, we generated Ccnb3 mutant mice by CRISPR/Cas9, and found that Ccnb3 mutation caused female infertility with the failure of metaphase-anaphase transition in meiosis I. Ccnb3 was necessary for APC/C activation to initiate anaphase I, but not required for oocytes maturation, meiosis II progression, or early embryonic development. Our study reveals the differential cell cycle regulation between meiosis I and meiosis II, as well as meiosis between males and females, which shed light on the cell cycle control of meiosis.\n\nHighlightsO_LIIdentification of a female meiosis-specific cyclin in mouse\nC_LIO_LICyclin B3 is required for metaphase-anaphase transition in oocyte meiosis I\nC_LIO_LICyclin B3 is not essential for oocyte maturation and sister chromosome segregation\nC_LIO_LICyclin B3 is necessary for APC/C activation and MPF kinase activity through Cdk1\nC_LI

cell biology↗

bioRxiv2018

Pericarp Pigmentation in ‘Red Delicious’ and Its Four Generation Mutants Correlates with Hormones

Bud sport mutants of apple (Malus domestica Borkh.) trees with a highly blushed colouring pattern are mainly caused by the accumulation of anthocyanins in the pericarp. Hormones are important factors modulating anthocyanin accumulation. However, a good understanding of the interplay between hormones and anthocyanin synthesis in apples, especially in mutants at the molecular level, remains elusive. Here, physiological and comparative transcriptome approaches were used to reveal the molecular basis of pericarp pigmentation in Red Delicious and its mutants, including Starking Red, Starkrimson, Campbell Redchief and Vallee spur, which were designated G0 to G4, respectively. Pericarp pigmentation gradually proliferated from G0 to G4. The anthocyanin content was higher in the mutants than in Red Delicious. The activation of early phenylpropanoid biosynthesis genes, including ASP3, PAL, 4CL, PER, CHS, CYP98A and F3H, was responsible for anthocyanin accumulation in mutants. In addition, IAA and ABA had a positive regulatory effect on the synthesis of anthocyanins, while GA had the reverse effect. The down-regulation of AACT1, HMGS, HMGR, MVK, MVD2, IDI1 and FPPS2 involved in terpenoid biosynthesis influences anthocyanin accumulation by positively regulating transcripts of AUX1 and SAUR that contribute to the synthesis of IAA, GID2 to GA, PP2C and SnRK2 to ABA. Furthermore, MYB and bHLH members, which are highly correlated (r=0.882-0.980) with anthocyanin content, modulated anthocyanin accumulation by regulating the transcription of structural genes, including CHS and F3H, involved in the flavonoid biosynthesis pathway.

bioinformatics↗

bioRxiv2018

Effects of CEPA and 1-MCP on flower bud differentiation of apple cv. ‘Nagafu No.2’ grafted on different rootstocks

The apple (Malus domestica Borkh.) has a relatively long juvenile period which prevent the fruit breeding. The understanding of the flowering system is important to improve breeding efficiency in the apple. In this context, 2-year-old \"Fuji\" apple cv. \"Nagafu No.2\" trees that were grafted on dwarf self-rooted rootstock M.26, vigorous rootstock M. sieversii and interstock M.26/M. sieversii, respectively. Spraying with clean water (as controls), 800 mg{middle dot}L-1 2-Chloroethylphosphonic acid (CEPA) and 2 L{middle dot}L-1 1-methylcyclopropene (1-MCP). The results showed that CEPA significantly repressed the vegetative growth attributed to the increase of the ABA and ZT synthesis, and the decrease of IAA synthesis in leaves and buds. However, there was no significant difference or significant inverse effect between 1-MCP and control. Furthermore, CEPA promoted flower formation, increased the flowering rate and advanced the blossom period for 2 days compared with the control, which accompanied by the accumulation of soluble sugar, glucose and sucrose, and the increase of -amylase (-AMY) and sucrose phosphate synthase (SPS) activities, and the decrease of the starch contents and sucrose synthase (SS) activities in leaves and buds. However, the blossom period was delayed for 2 days after spraying with 1-MCP. Finally, the expression of TFL1 was significantly repressed while the AP1 was significantly promoted in buds from M.26 and M.26/M. sieversii after spraying with CEPA, while the effect was not significant from M. sieversii. However, the expression levels of TFL1 and AP1 were not significantly different from the control after the application of 1-MCP. In spite of this, CEPA was more susceptible to easy-flowering M26, followed by M26/M. sieversii, and still less susceptible to difficult-flowering rootstock M. sieversii.\n\nAbbreviations

physiology↗

bioRxiv2017

Mapping Human Hematopoietic Hierarchy At Single Cell Resolution By Microwell-seq

The classical hematopoietic hierarchy, which is mainly built with fluorescence-activated cell sorting (FACS) technology, proves to be inaccurate in recent studies. Single cell RNA-seq (scRNA-seq) analysis provides a solution to overcome the limit of FACS-based cell type definition system for the dissection of complex cellular hierarchy. However, large-scale scRNA-seq is constrained by the throughput and cost of traditional methods. Here, we developed Microwell-seq, a high-throughput and low-cost scRNA-seq platform using extremely simple devices. Using Microwell-seq, we constructed a single-cell resolution transcriptome atlas of human hematopoietic differentiation hierarchy by profiling more than 50,000 single cells throughout adult human hematopoietic system. We found that adult human hematopoietic stem and progenitor cell (HSPC) compartment is dominated by progenitors primed with lineage specific regulators. Our analysis revealed differentiation pathways for each cell types, through which HSPCs directly progress to lineage biased progenitors before differentiation. We propose a revised adult human hematopoietic hierarchy independent of oligopotent progenitors. Our study also demonstrates the broad applicability of Microwell-seq technology.

cell biology↗