Molecular cloning of rice cDNAs related to pollen development using the subtraction hybridization technique

The meiotic stage of pollen mother cell is a very important stage in controlling the development and formation of pollen. In order to clone the rice cDNA(s) of this stage, a normal rice, Annong N and its thermosensitive mutant, Annong S-1 were used as the plant material. The mRNA has been extracted from the young panicle at the meiotic stage. By using the cDNA subtraction hybridization technique, three cDNA fragments, RP-1, RP-2 and RP-3 have been successfully cloned from Annong N. Northern blot analysis reveals that the mRNA of these three clones are expressed only in anthers, and not leaves. The mRNA levels of these clones are lower in anthers of Annong S-1 than in Annong N. Furthermore, the amount of mRNA extracted from anthers of Annong S-1 growing under high temperature (28℃) is lower than plants growing at lower temperature (25℃). Sequence analysis and homology search indicate that these three clones display no similarity to the current database. It is concluded that the three novel cDNA cloned are related to pollen development in rice.     

Construction and characterization of a normalized whole-life-cycle cDNA library of rice

A cDNA library with genomic complete coverage is a powerful tool for functional genomic studies.For studying the functions of rice genes on a large scale,a normalized whole-life-cycle cDNA library is constructed based on the strategy of saturation hybridization with genomic DNA using rice cultivar Minghui 63,an elite restorer line for a number of rice hybrids that are widely cultivated in China,This library consists of cDNA from 15 directionally cloned cDNA libraries constructed with different tissues from 9 developmental stages.For normalization,the denatured plasmids purified from the 15 directionally cloned libraries are mixed and hybridized with saturated genomic DNA labeled with magnetic beads in two complementary systems. Well-matched plasmids are captured from the hybridized genomic DNA and electroporated into competent DH10B E. coli for construction of the normalized whole-life-cycle cDNA library.This library consists of 62000 clones with an average insert length about 1.4kb.Inverse Northern blotting shows that this cDNA library included many rarely expressed genes and tissue-specific genes.Sequencing of 10750 cDNA clones of this library reveals 6399 unique EST s(expressed sequence tags),indicating that the non-redundancy of the library is about 59.5%.This library has been used to make cDNA microarrays for functional genomic studies.     

褐飞虱取食水稻幼苗cDNA文库的构建及筛选

以褐飞虱取食 3 2 h的水稻幼苗为材料构建了 c DNA文库 ,初始文库含 3 .2× 1 0 6 个克隆 ,重组率为 86%,取 1 .0× 1 0 6个克隆子扩增一次 ,收集到 80 m L滴度为 1 .2× 1 0 9pfu/ m L的扩增文库 .随机挑取 2 0个克隆以 T7和 M1 3 reverse为引物进行 PCR扩增 ,以鉴定插入片段的大小 ,结果发现多数片段的长度在 1～ 4.0Kb左右 ,少数片段在 4Kb以上 ,个别片段在 6Kb左右 .以在受褐飞虱取食的水稻幼苗中特异表达的 ESTBp Hi0 0 8为探针 ,筛选 c DNA文库 ,得到该基因的 c DNA全长     

水稻雄性不育突变体OsMS121的遗传及定位分析

通过射线诱变粳稻9522种子获得一株水稻雄性不育突变体OsMS121．遗传分析的结果显示突变体是单基因隐性突变．细胞学观察发现突变体花粉的萌发孔在发育过程中出现异常．萌发孔的塞子体积较小,且畸形．萌发孔的孢粉素层与野生型相比较为稀疏;环状突起不明显,结构松散,呈颗粒状．用图位克隆的方法将该基因定位在水稻第二条染色体分子标记R2M16—2和R2M18—1之间约200KB范围内．这些结果为该基因的克隆及其在花粉发育中的功能研究奠定了基础。     

Cloning and expressional analyses of a cinnamoyl CoA reductase cDNA from rice seedlings

Cinnamoyl CoA reductase (CCR: EC 1.2.1.44),the entry-point enzyme of the llgnin specific biosynthetic pathway, catalyzes the conversion of cinnamoyl CoA esters to their corresponding dnnamaldehydes. Multiple sequence alignment showed that the deduced polypeptide shared 70% similarity and 30% sequence identity at the amino acid level with defined CCR genes from other plant species and they all contain the common signature sequences thought to be the catalytic site as well as the putative NADP binding domain.Using a conserved OsCCR cDNA fragment as the probe for library screening, we isolated the genomic DNA that covered the whole coding region of OsCCR with total length of 3045bp including 4 introns and 5 exons. The open reading frame for our OsCCR gene coBtAin~ 337 amino adds. Northern blot indicated that OsCCR was expressed in different organs with the highest level found in stems. In situ hybridization results showed that OsCCR mRNA was localized mainly along the vascular bundles in stems and leaves, and also in lateral roots that was differentiating from the tiilering node. We conclude that the vascular-localized expression of OsCCR gene may suggest its possible involvement in llgnin biosynthesis. Cloning and characterization of OsCCR will help to clarify how llgniflcations in plants are regulated and will provide a physical basis for creating genetically engineered rice plants with optimal lignin contents.     

蝴蝶兰查尔酮合酶基因cDNA的克隆、鉴定及其原核表达

利用逆转录．聚合酶链式反应(RT-PCR)得到在蝴蝶兰花瓣中特异性表达的查尔酮合酶cDNA(pchs-1)．DNA序列分析表明,该序列与已发表的查尔酮合酶基因有很高的同源性．将此cDNA序列不改变阅读框架克隆到pET-24α( )原核表达载体上,经IPTG诱导后,SDS-PAGE的结果表明有预测大小的蛋白受诱导表达,该基因在植物中的功能验证工作正在进行中．     

水稻温敏核不育系HD9802S不育性遗传的初步观察

以水稻温敏核不育系HD9802S配组的HD9802S／湘早92和HD9802S／荆楚15的F1和F2代为材料,对这两个杂交早籼稻组合F2群体的花粉育性进行了观察分析．结果表明,F2群体中可育株数和不育株数经卡平方测验符合3：1的理论比例,初步确定温敏核不育系HD9802S的雄性不育性由一对主效隐性核基因控制;同时根据F2群体花粉育性表现出连续分布的特征,推测其雄性不育性还受其他微效基因的影响。     

UDP-glucose pyrophosphorylase2 (OsUgp2), a pollen-preferential gene in rice, plays a critical role in starch accumulation during pollen maturation

UDP-glucose pyrophosphorylase (UGPase) is predominantly present and plays significant role in carbohydrate metabolism in plants. Two homologous UGPase genes, OsUgp1 and OsUgp2, exist in rice genome. OsUgp1 has recently been reported to be essential for callose deposition during pollen mother cell and meiosis stages as well as for seed carbohydrate metabolism. In this study, a full-length cDNA of OsUgp2 was isolated from rice anther. Northern blot and RNA in situ hybridization indicated that the expression o...     

Sequence analysis of mRNA polyadenylation signals of rice genes

Most eukaryotic mRNAs receive a poly (A) tail at their 3′-ends through a process involving the cleavage of pre-mRNA and the concomitant polymerization of adenosine residues to the cleaved RNA end[1,2]. As un- translated regions (UTRs) may contain importa…     

Cloning and expression analysis of MBLL cDNA

The mbl (muscleblind) gene of Drosophila encodes a nuclear protein which contains two Cys3His motifs. The mutation of mbl gene will disturb the differentiation of all the Drosophila's photoreceptors. Primers have been designed according to human EST086139, which is highly homologous to mbl gene. Human fetal brain cDNA library has been screened and a novel cDNA clone has been obtained. The 2595 bp cDNA, designated MBLL (muscleblind-like), contains an open reading frame which encodes 255 amino acids and has 4 Cys3His motifs (GenBank Acc. AF061261). The amino acids sequence shares high homology to Drosophila's mbl. The Northern blot and RNA dot blot hybridization of 43 human adult tissues and 7 fetal tissues show that MBLL is a widely expressed gene, but the expression amounts differ in these tissues.     

水稻全长均一化cDNA文库构建及SDG725结合蛋白筛选

为了筛选水稻组蛋白甲基转移酶SDG725的结合蛋白,构建了水稻全长均一化cDNA文库,以SDG725C末端为诱饵蛋白对cDNA文库进行筛选.最后筛选到70个可能与SDG725相互作用的蛋白,同时对筛选出的候选蛋白进行GO功能分析和亚细胞定位预测,并对部分蛋白与蛋白相互作用进行了验证.研究结果发现筛选到的结合蛋白有17%位于细胞核中,更多位于核外,为进一步研究SDG725的生物学功能提供理论基础.     

Molecular evolution of the exon 2 of CHS genes and the possibility of its application to plant phylogenetic analysis

The exon 2 of chalcone synthase (CHS) gene is relatively conserved during evolution. In this study, three exon 2 fragments from two species in gymnosperm (Cycas panzhihuaensis, Ginkgo biloba) and seven from four species in angiosperm (Magnolia denudata, Salix babylonica, Nymphaea tetragona, Camellia japonica) have been amplified by PCR from genomic DNA and sequenced. Together with other 73 sequences ofCHS collected from EMBL database and literature, these sequences, which embrace 19 families of gymnosperm and angiosperm, have been analyzed for their phylogenetic relations by parsimony method. The result indicated that sequences from the same systematic family usually grouped together except those from Theaceae, Magnoliaceae and Nymphaeaceae. The relative rate test revealed the rate heterogeneity of CHS genes among the families. For the nucleotide substitution the sequences from Asteraceae and Solanaceae evolve faster than those from the other families analyzed while the sequences from Poaceae, Asteraceae and Solanaceae evolve faster for the nonsynonymous substitution. These results suggest that the duplication and extinction events of CHS genes are different among systematic families, therefore it seems impractical to look for orthologous sequences from CHS genes to study plant phylogeny at the family level andlor above. However, it is possible to do so below the family level.     

人类Neuritin cDNA的克隆和表达

从人胎脑cDNA文库筛选出一条1618bp的cDNA。此cDNA含有一个426bp的最大开放阅读框,编码一个142个氨基酸的蛋白质,预测分子质量为15.3ku。与目前数据库中序列比较,该cDNA与鼠neuritin基因同源性达98％。多组织Northern blot分析显示neuritin在脑组织高度表达。neuritin cDNA的读框片段正确插入到pQE40表达载体中,获得了预期的表达产物,并初步得到了其纯化蛋白。     

Cloning and expression of a cDNA encoding ribosomal protein S4 from Rice (Oryza sativa)

A cDNA clone, pS4, has been isolated from a cDNA library prepared from rice anthers of about 1.0 mm in length. DNA sequence analysis and database search show that the cDNA encodes a protein which is highly homologous to eukaryotic 80S ribosomal protein subunit 4 (S4). Northern hybridization indicates that this gene expresses in all tissues analyzed although the expression level varies and it cannot be induced by mechanical wounding in leaves. Southern blot analysis demonstrates that this rice S4 gene is from a multigene family.     

Cloning and expression of a cDNA encoding ribosomal protein S4 from Rice (Oryza sativa)

A cDNA clone, pS4, has been isolated from a cDNA library prepared from rice anthers of about 1.0 mm in length. DNA sequence analysis and database search show that the cDNA encodes a protein which is highly homologous to eukaryotic 80s ribosomal protein subunit 4 (S4). Northern hybridization indicates that this gene expresses in all tissues analyzed although the expression level varies and it cannot be induced by mechanical wounding in leaves. Southern blot analysis demonstrates that this riceS4 gene is from a multigene family.