Transport of photoassimilates from leaf tissues (source regions) to the sink organs is essential for plant development. Here, we show that a phytohormone, the brassinosteroids (BRs) promotes pollen and seed development in rice by directly promoting expression of Carbon Starved Anther (CSA) which encodes a MYB domain protein. Over‐expression of the BR‐synthesis gene D11 or a BR‐signaling factor OsBZR1 results in higher sugar accumulation in developing anthers and seeds, as well as higher grain yield compared with control non‐transgenic plants. Conversely, knockdown of D11 or OsBZR1 expression causes defective pollen maturation and reduced seed size and weight, with less accumulation of starch in comparison with the control. Mechanically, OsBZR1 directly promotes CSA expression and CSA directly triggers expression of sugar partitioning and metabolic genes during pollen and seed development. These findings provide insight into how BRs enhance plant reproduction and grain yield in an important agricultural crop. 相似文献
South‐East Asia covers four of the world's biodiversity hotspots, showing high species diversity and endemism. Owing to the successive expansion and contraction of distribution and the fragmentation by geographical barriers, the tropical flora greatly diversified in this region during the Tertiary, but the evolutionary tempo and mode of species diversity remain poorly investigated. Paphiopedilum, the largest genus of slipper orchids comprising nearly 100 species, is mainly distributed in South‐East Asia, providing an ideal system for exploring how plant species diversity was shaped in this region. Here, we investigated the evolutionary history of this genus with eight cpDNA regions and four low‐copy nuclear genes. Discordance between gene trees and network analysis indicates that reticulate evolution occurred in the genus. Ancestral area reconstruction suggests that vicariance and long‐distance dispersal together led to its current distribution. Diversification rate variation was detected and strongly correlated with the species diversity in subg. Paphiopedilum (~80 species). The shift of speciation rate in subg. Paphiopedilum was coincident with sea‐level fluctuations in the late Cenozoic, which could have provided ecological opportunities for speciation and created bridges or barriers for gene flow. Moreover, some other factors (e.g. sympatric distribution, incomplete reproductive barriers and clonal propagation) might also be advantageous for the formation and reproduction of hybrid species. In conclusion, our study suggests that the interplay of reticulate evolution and sea‐level fluctuations has promoted the diversification of the genus Paphiopedilum and sheds light into the evolution of Orchidaceae and the historical processes of plant species diversification in South‐East Asia. 相似文献
Nine tilapia Oreochromis niloticus group B streptococcus (GBS) strains differing in serotype and genotype were selected and paired. Two‐dimensional difference gel electrophoresis (2D DIGE) and matrix‐assisted laser‐desorption ionization time‐of‐flight‐mass spectrometry (MALDI‐TOF‐MS) were used to analyse the protein profiles of the strain pairs. Forty‐three proteins corresponding to 66 spots were identified, of which 35 proteins were found in the seven selected strain pairs that represented pairs differing in genotype and serotype. Among the 35 proteins, numbers of differentially expressed proteins in strains of different serotypes were greater than found in strains of different genotypes, suggesting that serotype plays a more essential role than genotype in the differential protein expression among GBS strains. No distinct pattern was found with respect to genotype and the protein expression profile of GBS strains. Several proteins were identified as surface‐associated cytoplasmic proteins that possessed the typical immunity‐eliciting characteristics of surface proteins. The identified proteins were found to be involved in 16 biological processes and seven Kyoto encyclopaedia of genes and genomes (KEGG) pathways. The data, for the first time, identified differentially expressed proteins in O. niloticus GBS strains of different serotypes, which play a major role in immunogenicity of O. niloticus GBS than does genotype, offering further information for design of a vaccine against O. niloticus GBS. 相似文献
α1‐adrenoceptors (α1‐ARs) stimulation has been found to enhance excitatory processes in many brain regions. A recent study in our laboratory showed that α1‐ARs stimulation enhances glutamatergic transmission via both pre‐ and post‐synaptic mechanisms in layer V/VI pyramidal cells of the rat medial prefrontal cortex (mPFC). However, a number of pre‐synaptic mechanisms may contribute to α1‐ARs‐induced enhancement of glutamate release. In this study, we blocked the possible post‐synaptic action mediated by α1‐ARs to investigate how α1‐ARs activation regulates pre‐synaptic glutamate release in layer V/VI pyramidal neurons of mPFC. We found that the α1‐ARs agonist phenylephrine (Phe) induced a significant enhancement of glutamatergic transmission. The Phe‐induced potentiation was mediated by enhancing pre‐synaptic glutamate release probability and increasing the number of release vesicles via a protein kinase C‐dependent pathway. The mechanisms of Phe‐induced potentiation included interaction with both glutamate release machinery and N‐type Ca2+ channels, probably via a pre‐synaptic Gq/phospholipase C/protein kinase C pathway. Our results may provide a cellular and molecular mechanism that helps explain α1‐ARs‐mediated influence on PFC cognitive functions.
Miniature chromosome maintenance 7 (MCM7) is an essential component of DNA replication licensing complex. Recent studies indicate that MCM7 is amplified and overexpressed in a variety of human malignancies. In this report, we show that MCM7 binds SF3B3. The binding motif is located in the N terminus (amino acids 221–248) of MCM7. Knockdown of MCM7 or SF3B3 significantly increased unspliced RNA of epidermal growth factor receptor, platelet-derived growth factor receptor, and c-Met. A dramatic drop of reporter gene expression of the oxytocin exon 1-intron-exon 2-EGFP construct was also identified in SF3B3 and MCM7 knockdown PC3 and DU145 cells. The MCM7 or SF3B3 depleted cell extract failed to splice reporter RNA in in vitro RNA splicing analyses. Knockdown of SF3B3 and MCM7 leads to an increase of cell death of both PC3 and DU145 cells. Such cell death induction is partially rescued by expressing spliced c-Met. To our knowledge, this is the first report suggesting that MCM7 is a critical RNA splicing factor, thus giving significant new insight into the oncogenic activity of this protein. 相似文献
Alternative splicing is prevalent in plants, but little is known about its regulation in the context of developmental and signaling pathways. We describe here a new factor that influences pre-messengerRNA (mRNA) splicing and is essential for embryonic development in Arabidopsis thaliana. This factor was retrieved in a genetic screen that identified mutants impaired in expression of an alternatively spliced GFP reporter gene. In addition to the known spliceosomal component PRP8, the screen recovered Arabidopsis RTF2 (AtRTF2), a previously uncharacterized, evolutionarily conserved protein containing a replication termination factor 2 (Rtf2) domain. A homozygous null mutation in AtRTF2 is embryo lethal, indicating that AtRTF2 is an essential protein. Quantitative RT-PCR demonstrated that impaired expression of GFP in atrtf2 and prp8 mutants is due to inefficient splicing of the GFP pre-mRNA. A genome-wide analysis using RNA sequencing indicated that 13–16% of total introns are retained to a significant degree in atrtf2 mutants. Considering these results and previous suggestions that Rtf2 represents an ubiquitin-related domain, we discuss the possible role of AtRTF2 in ubiquitin-based regulation of pre-mRNA splicing. 相似文献