拟南芥根的辐射形态相关基因SHORT-ROOT研究进展

从模式植物拟南芥中克隆得到的SHORT-ROOT基因（SHR）被证明参与根部形态建成途径。目前已知SHR是与根辐射形态直接相关的重要调控因子,同时也参与维持根尖分生组织的活性。SHR既作为转录因子启动下游基因的表达,又作为短程信号调节根的发育。本文综述了SHR相关研究进展,并展望其研究前景。     

ATMYB123和ATKOR1基因参与拟南芥根发育的调控

从拟南芥T-DNA插入突变体库中筛选到2个根发育相关基因ATMYB123和ATKOR1表达缺失的突变体atmyb123和atkor1,通过杂交构建这两个基因表达缺失的双突变体atmyb123/atkor1,以明确这两个基因在根发育中的作用。结果显示:(1)ATMYB123表达缺失突变体atmyb123植株地上部分发育减缓,种皮颜色变黄,而ATKOR1表达缺失突变体atkor1植株在这两方面与其野生型没有明显差异;两基因缺失均显著影响了拟南芥根的发育,根生长受到了严重抑制。(2)双突变体atmyb123/atkor1在植株形态和种皮颜色方面表现出单突变体AT-MYB123的特点,而其根长却介于两单突变体的中间。(3)进一步研究发现,培养基pH改变、NaCl处理、外源GA施用均没有改变突变体根生长趋势,显示这3种因素与两基因缺失突变引起的根发育抑制无关。研究表明,AT-MYB123和ATKOR1基因参与拟南芥根的发育调控,转录因子ATMYB123可能作为主调控因子参与ATKOR1对拟南芥根发育的调控。     

细胞分裂素响应调节因子介导拟南芥生长发育的作用研究

细胞分裂素作为重要的植物激素广泛参与植物生长发育。尽管细胞分裂素的作用已经广为人知,但是作为激素信号的效应器,其响应调节因子的作用未见综合报道。现就以拟南芥为例,介绍拟南芥响应调节因子在根生长发育、顶端分生组织发育及叶子形态发生中的作用。     

缬沙坦抑制SHR心血管重构涉及降钙素基因相关肽的初步研究

缬沙坦是临床常用的抗高血压药物,除降压外其对心血管重构的作用也逐渐引起人们的重视.降钙素基因相关肽(calcitonin gene related peptide,CGRP)是目前已知的最强舒血管物质,也参与了心血管重构的过程.以缬沙坦治疗自发性高血压大鼠(spontaneously hypertensive rats,SHR)8周,能明显降低SHR血压,抑制心肌肥厚,改善心室重构,同时也显著抑制胸主动脉和肠系膜上动脉血管重构.缬沙坦治疗还显著升高SHR大鼠血浆CGRP浓度,上调背根神经节和肠系膜上动脉中CGRP表达.结果提示,缬沙坦降低SHR大鼠血压,改善心血管重构,其作用可能与提高CGRP水平有关.     

蒙古沙冬青AmDREB2.1基因的克隆及表达分析

基于已建立的蒙古沙冬青[Ammopiptanthus mongolicus(Masxim.)Cheng f.]根的转录本数据库,分离到1个编码DREB类转录因子基因,命名为AmDREB2.1。该序列全长978 bp,包括531 bp的开放阅读框(ORF),编码176个氨基酸,具有典型的DREB转录因子保守的AP2结构域。实时荧光定量PCR分析表明,该基因能在根、叶中表达,但对干旱、低温响应不同,AmDREB2.1主要参与根的干旱胁迫应答。     

白念珠菌形态转换及其调控机制的研究进展

白念珠菌是人体内正常的共生微生物,也是最常见的机会性致病真菌。该菌最重要的生物学特征是其形态的多样性,不同形态细胞之间可频繁地相互转换。这种形态的可塑性与白念珠菌在宿主体内的定植能力、侵染性以及有性生殖等方面均有密切关系,也是该菌对外界环境变化的适应策略。酵母–菌丝相和white-opaque形态转换是白念珠菌中两种典型形态转换系统。宿主相关的环境因子和白念珠菌内源基因共同参与这些形态转换的调控。该文将综述近年来白念珠菌形态转换及其调控机制方面的进展,重点介绍参与菌丝发育和white-opaque形态转换的关键因子和调控通路。     

钙调磷酸酶调节因子1在疾病发生中的研究进展北大核心

钙调磷酸酶调节因子1基因是新兴发现的致病基因,该文综述近几年该基因与疾病研究的最新进展,为相关疾病的治疗提供思路。该文依次介绍钙调磷酸酶调节因子1基因及其表达方式,该基因参与三种疾病的方式的异同,并罗列了目前研究中遇到的问题,提出有效的措施,最后对该基因在疾病治疗中的应用进行展望。钙调磷酸酶调节因子1基因作为一个致病基因,其涉及疾病广泛多样,深入了解其作用机制,对疾病的治疗将大有好处。     

钙调磷酸酶调节因子1在疾病发生中的研究进展

钙调磷酸酶调节因子1基因是新兴发现的致病基因,该文综述近几年该基因与疾病研究的最新进展,为相关疾病的治疗提供思路。该文依次介绍钙调磷酸酶调节因子1基因及其表达方式,该基因参与三种疾病的方式的异同,并罗列了目前研究中遇到的问题,提出有效的措施,最后对该基因在疾病治疗中的应用进行展望。钙调磷酸酶调节因子1基因作为一个致病基因,其涉及疾病广泛多样,深入了解其作用机制,对疾病的治疗将大有好处。     

人类miRNA上游转录因子及下游靶基因的基因本体分析

目的研究人类miRNA转录因子及靶基因之间的相关关系。方法利用生物信息学方法预测miR-NA的上游转录因子和下游靶基因,并对预测结果做基因本体分析,得到参与各生物学过程及分子功能的比例,用统计学软件PASW做相关性分析。结果人类382个miRNA参与应激、代谢、发育等10个生物学过程和行使转录调控、翻译调控、催化活性等12个分子功能,miRNA上游转录因子之间、下游靶基因之间以及上下游之间存在着广泛的正负相关关系。结论基因在参与生物学过程及行使分子功能的过程中,通过miRNA实现协同作用或隔离效应。     

大肠癌患者生存相关基因的筛选与网络调控分析

本研究筛选了与大肠癌患者生存期相关的关键基因,以探索这些基因所参与的信号调控网络.在前期研究中,通过对大肠癌相关表达谱数据GSE17538使用显著性分析软件SAM3.01对大肠癌患者生存期相关的基因进行筛选,得到了与大肠癌患者生存期相关的基因235个.对这235个基因进行以下筛选和分析:首先对235个基因进行转录因子结合位点富集分析,筛选含有转录因子结合位点数目大于7个的基因,再将这些基因与大肠癌上调基因集取交集,最后将筛选出的基因进行生存分析及网络调控分析,明确这些基因与大肠癌患者生存期的关系及在大肠癌细胞信号调控网络中所参与的信号网络.通过上述分析筛选出的与大肠癌患者生存期相关,受转录因子调控较多,且在大肠癌中表达上调的基因有6个,分别为STX2,PODXL,KLK6,GRB10,EHBP1和CREB5.这些基因所参与的信号调控网络与大肠癌转移相关信号通路相关.大肠癌患者生存期与大肠癌转移密切相关,生存期相关的6个基因通过调控大肠癌转移相关信号通路影响患者的生存期.     

SHORT-ROOT regulates vascular patterning,but not apical meristematic activity in the Arabidopsis root through cytokinin homeostasis

SHORT-ROOT (SHR) is a key regulator of radial patterning and stem-cell renewal in the Arabidopsis root. Although SHR is expressed in the stele, its function in the vascular tissue was not recognized until recently. In shr, the protoxylem is missing due to the loss of expression of microRNA165A (miR165A) and microRNA166B (miR165B). shr is also defective in lateral root formation, but the mechanism remains unclear. To dissect the SHR developmental pathway, we recently have identified its direct targets at the genome scale by chromatin immunoprecipitation followed by microarray analysis (ChIP-chip). In further studies, we have shown that SHR regulates cytokinin homeostasis through cytokinin oxidase 3 and that this role of SHR is critical to vascular patterning in the root. In this communication we report that SHR also regulates miR165A and miR166B indirectly through its effect on cytokinin homeostasis. Although cytokinin is inhibitory to root growth, the root-apical-meristem defect in shr was not alleviated by reduction of endogenous cytokinin. These results together suggest that SHR regulates vascular patterning, but not root apical meristematic activity, through cytokinin homeostasis.     

Reduced expression of the SHORT-ROOT gene increases the rates of growth and development in hybrid poplar and Arabidopsis

SHORT-ROOT (SHR) is a well characterized regulator of cell division and cell fate determination in the Arabidopsis primary root. However, much less is known about the functions of SHR in the aerial parts of the plant. In this work, we cloned SHR gene from Populus trichocarpa (PtSHR1) as an AtSHR ortholog and down-regulated its expression in hybrid poplar (Populus tremula×P. tremuloides Michx-clone T89) in order to determine its physiological functions in shoot development. Sharing a 90% similarity to AtSHR at amino acid level, PtSHR1 was able to complement the Arabidopsis shr mutant. Down regulation of PtSHR1 led to a strong enhancement of primary (height) and secondary (girth) growth rates in the transgenic poplars. A similar approach in Arabidopsis showed a comparable accelerated growth and development phenotype. Our results suggest that the response to SHR could be dose-dependent and that a partial down-regulation of SHR could lead to enhanced meristem activity and a coordinated acceleration of plant growth in woody species. Therefore, SHR functions in plant growth and development as a regulator of cell division and meristem activity not only in the roots but also in the shoots. Reducing SHR expression in transgenic poplar was shown to lead to significant increases in primary and secondary growth rates. Given the current interest in bioenergy crops, SHR has a broader role as a key regulator of whole plant growth and development and SHR suppression has considerable potential for accelerating biomass accumulation in a variety of species.     

Short-Root regulates primary, lateral, and adventitious root development in Arabidopsis

Short-Root (SHR) is a well-characterized regulator of radial patterning and indeterminacy of the Arabidopsis (Arabidopsis thaliana) primary root. However, its role during the elaboration of root system architecture remains unclear. We report that the indeterminate wild-type Arabidopsis root system was transformed into a determinate root system in the shr mutant when growing in soil or agar. The root growth behavior of the shr mutant results from its primary root apical meristem failing to initiate cell division following germination. The inability of shr to reactivate mitotic activity in the root apical meristem is associated with the progressive reduction in the abundance of auxin efflux carriers, PIN-FORMED1 (PIN1), PIN2, PIN3, PIN4, and PIN7. The loss of primary root growth in shr is compensated by the activation of anchor root primordia, whose tissues are radially patterned like the wild type. However, SHR function is not restricted to the primary root but is also required for the initiation and patterning of lateral root primordia. In addition, SHR is necessary to maintain the indeterminate growth of lateral and anchor roots. We conclude that SHR regulates a wide array of Arabidopsis root-related developmental processes.