The diverse members of the genus Daphne are prized for their fragrant flowers.Despite being promising ornamental plants in many countries,genetic information of Daphne is scarce.In this study,the plastomes of four spe...The diverse members of the genus Daphne are prized for their fragrant flowers.Despite being promising ornamental plants in many countries,genetic information of Daphne is scarce.In this study,the plastomes of four species and one variety of Daphne were sequenced and analyzed.The plastomes were typical and contained a pair of inverted repeat(IR)regions that separated the large single-copy(LSC)region from the small single-copy(SSC)region.With a length ranging from 132,869 bp(D.genkwa)to 174,773 bp(D.championii),106 to 141 genes were predicted.Comparative plastome analysis of the newly sequenced plastomes with four publicly available Daphne plastomes identified an expansion of the IRs,sequence variations,and mutational hotspots.Phylogenetic analyses indicated that the genus Daphne in its current circumscription is polyphyletic.Daphne genkwa was nested within the genus Wikstroemia,while D.championii was well resolved as sister to Edgeworthia.These findings concurred with results from our study that used nuclear ribosomal internal transcribed spacer sequence data.The conflicts on the molecular placement of D.championii and D.genkwa and the present taxonomic classification in Daphne suggest that a new intergeneric classification system of Daphneae warrants consideration.展开更多
N-methyl-D-aspartate receptors（NMDARs）, a subtype of glutamate-gated ion channels, play a central role in epileptogenesis. Recent studies have identified an increasing number of GRIN2 A（a gene encoding the NMDAR Gl...N-methyl-D-aspartate receptors（NMDARs）, a subtype of glutamate-gated ion channels, play a central role in epileptogenesis. Recent studies have identified an increasing number of GRIN2 A（a gene encoding the NMDAR GluN2A subunit） mutations in patients with epilepsy. Phenotypes of GRIN2 A mutations include epilepsy-aphasia disorders and other epileptic encephalopathies, which pose challenges in clinical treatment. Here we identified a heterozygous GRIN2 A mutation（c.1341 T[A, p.N447 K） from a boy with Rolandic epilepsy by whole-exome sequencing. The patient became seizurefree with a combination of valproate and lamotrigine.Functional investigation was carried out using recombinant NMDARs containing a GluN2A-N447 K mutant that is located in the ligand-binding domain of the GluN2A subunit. Whole-cell current recordings in HEK 293 T cells revealed that the N447 K mutation increased the NMDAR current density by;.2-fold, enhanced the glutamate potency by 2-fold, and reduced the sensitivity to Mg;inhibition. These results indicated that N447 K is a gain-offunction mutation. Interestingly, alternative substitutions by alanine and glutamic acid at the same residue（N447 A and N447 E） did not change NMDAR function, suggesting a residual dependence of this mutation in altering NMDAR function. Taken together, this study identified human GluN2A N447 K as a novel mutation associated with epilepsy and validated its functional consequences in vitro.Identification of this mutation is also helpful for advancing our understanding of the role of NMDARs in epilepsy and provides new insights for precision therapeutics in epilepsy.展开更多
基金supported by the Fundamental Research Funds for the Central Universities(33000-31611215)the Guangzhou Science and Technology Program(201903010076)the National Natural Science Foundation of China(31760048).
文摘The diverse members of the genus Daphne are prized for their fragrant flowers.Despite being promising ornamental plants in many countries,genetic information of Daphne is scarce.In this study,the plastomes of four species and one variety of Daphne were sequenced and analyzed.The plastomes were typical and contained a pair of inverted repeat(IR)regions that separated the large single-copy(LSC)region from the small single-copy(SSC)region.With a length ranging from 132,869 bp(D.genkwa)to 174,773 bp(D.championii),106 to 141 genes were predicted.Comparative plastome analysis of the newly sequenced plastomes with four publicly available Daphne plastomes identified an expansion of the IRs,sequence variations,and mutational hotspots.Phylogenetic analyses indicated that the genus Daphne in its current circumscription is polyphyletic.Daphne genkwa was nested within the genus Wikstroemia,while D.championii was well resolved as sister to Edgeworthia.These findings concurred with results from our study that used nuclear ribosomal internal transcribed spacer sequence data.The conflicts on the molecular placement of D.championii and D.genkwa and the present taxonomic classification in Daphne suggest that a new intergeneric classification system of Daphneae warrants consideration.
基金supported by the grants of the National Natural Science Foundation of China(81671162,81521062,81561168,and 81571273)the National Basic Research Development Program of China(2014CB910300 and 2013CB530904)Key Research Project of the Ministry of Science and Technology of China(2016YFC0904400)
文摘N-methyl-D-aspartate receptors（NMDARs）, a subtype of glutamate-gated ion channels, play a central role in epileptogenesis. Recent studies have identified an increasing number of GRIN2 A（a gene encoding the NMDAR GluN2A subunit） mutations in patients with epilepsy. Phenotypes of GRIN2 A mutations include epilepsy-aphasia disorders and other epileptic encephalopathies, which pose challenges in clinical treatment. Here we identified a heterozygous GRIN2 A mutation（c.1341 T[A, p.N447 K） from a boy with Rolandic epilepsy by whole-exome sequencing. The patient became seizurefree with a combination of valproate and lamotrigine.Functional investigation was carried out using recombinant NMDARs containing a GluN2A-N447 K mutant that is located in the ligand-binding domain of the GluN2A subunit. Whole-cell current recordings in HEK 293 T cells revealed that the N447 K mutation increased the NMDAR current density by;.2-fold, enhanced the glutamate potency by 2-fold, and reduced the sensitivity to Mg;inhibition. These results indicated that N447 K is a gain-offunction mutation. Interestingly, alternative substitutions by alanine and glutamic acid at the same residue（N447 A and N447 E） did not change NMDAR function, suggesting a residual dependence of this mutation in altering NMDAR function. Taken together, this study identified human GluN2A N447 K as a novel mutation associated with epilepsy and validated its functional consequences in vitro.Identification of this mutation is also helpful for advancing our understanding of the role of NMDARs in epilepsy and provides new insights for precision therapeutics in epilepsy.
