Single-stranded DNA-binding proteins(SSBs)play essential roles in the replication,recombination and repair processes of organellar DNA molecules.In Arabidopsis thaliana,SSBs are encoded by a small family of two genes(...Single-stranded DNA-binding proteins(SSBs)play essential roles in the replication,recombination and repair processes of organellar DNA molecules.In Arabidopsis thaliana,SSBs are encoded by a small family of two genes(SSB1 and SSB2).However,the functional divergence of these two SSB copies in plants remains largely unknown,and detailed studies regarding their roles in the replication and recombination of organellar genomes are still incomplete.In this study,phylogenetic,gene structure and protein motif analyses all suggested that SSB1 and SSB2 probably diverged during the early evolution of seed plants.Based on accurate long-read sequencing results,ssb1 and ssb2 mutants had decreased copy numbers for both mitochondrial DNA(mtDNA)and plastid DNA(ptDNA),accompanied by a slight increase in structural rearrangements mediated by intermediate-sized repeats in mt genome and small-scale variants in both genomes.Our findings provide an important foundation for further investigating the effects of DNA dosage in the regulation of mutation frequencies in plant organellar genomes.展开更多
文摘目的分析抗干燥综合征抗原B(Sjogren’s syndrome antigen B,SSB)抗体阳性同时抗干燥综合征抗原A(Sjogren’s syndrome antigen A,SSA)抗体阴性的原发性干燥综合征(primary Sjogren’s syndrome,pSS)患者的临床特点。方法回顾性分析2016年5月至2022年1月在国家风湿病数据中心(Chinese Rheumatism Data Center,CRDC)注册登记的pSS患者临床资料,比较抗SSB抗体阳性同时抗SSA抗体阴性pSS患者(观察组)与抗SSA抗体阳性(抗SSB抗体阳性或阴性)pSS患者(对照组)的临床特点差异。结果共纳入pSS患者8188例,其中女性7801例,男性387例,中位年龄51(40,59)岁。观察组pSS患者101例(1.2%),对照组8087例(98.8%),两组患者的性别、年龄及病程比较差异均无统计学意义(P均>0.05)。临床特征方面,相较于对照组,观察组出现口干(97.0%比88.5%,P<0.05)、腮腺肿大(31.7%比17.5%,P<0.05)的比例更高,EULAR干燥综合征患者报告指数(European League Against Rheumatism Sjogren’s Syndrome Patient Reported Index,ESSPRI)中ESSPRI干燥评分[50.0(39.3,60.0)比41.0(23.0,60.0),P<0.05]、ESSPRI疲乏评分[50.0(23.8,59.8)比34.0(15.0,52.0),P<0.05]、ESSPRI肢体痛评分[50.0(20.0,55.8)比20.0(0.0,42.0),P<0.05]均更高,医生总体评估(Physician’s Global Assessment,PGA)评分[1.3(0.8,1.6)比1.0(0.5,1.5),P<0.05]也更高,但观察组EULAR干燥综合征疾病活动指数(European League Against Rheumatism Sjogren’s Syndrome Disease Activity Index,ESSDAI)评分低于对照组[2.0(0.0,5.0)比4.0(0.0,9.0),P<0.05]。结论抗SSB抗体阳性同时抗SSA抗体阴性的pSS患者更易出现腮腺肿大和口干。
基金supported by grants from the National Natural Science Foundation of China(32170238,32400191)Guangdong Basic and Applied Basic Research Foundation(2023A1515111029)+2 种基金the Science,Technology and Innovation Commission of Shenzhen Municipality(RCYX20200714114538196)the Chinese Academy of Agricultural Sciences Elite Youth Program(grant 110243160001007)the Guangdong Pearl River Talent Program(2021QN02N792)。
文摘Single-stranded DNA-binding proteins(SSBs)play essential roles in the replication,recombination and repair processes of organellar DNA molecules.In Arabidopsis thaliana,SSBs are encoded by a small family of two genes(SSB1 and SSB2).However,the functional divergence of these two SSB copies in plants remains largely unknown,and detailed studies regarding their roles in the replication and recombination of organellar genomes are still incomplete.In this study,phylogenetic,gene structure and protein motif analyses all suggested that SSB1 and SSB2 probably diverged during the early evolution of seed plants.Based on accurate long-read sequencing results,ssb1 and ssb2 mutants had decreased copy numbers for both mitochondrial DNA(mtDNA)and plastid DNA(ptDNA),accompanied by a slight increase in structural rearrangements mediated by intermediate-sized repeats in mt genome and small-scale variants in both genomes.Our findings provide an important foundation for further investigating the effects of DNA dosage in the regulation of mutation frequencies in plant organellar genomes.
