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EST(expressed sequence tags ,EST) 是一段长约150~500 bp的基因表达的外源序列片段,是由大规模随机挑取的cDNA克隆测序得到的组织或细胞基因组的表达序列标签。一个EST代表生物某一时期的某种组织或细胞的一个表达基因。本文主要综述了EST技术的原理方法,哺乳动物早期胚胎研究的理论基础以及EST技术在早期胚胎研究方面的应用,并讨论了利用EST进行研究分析的发展趋势。 相似文献
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Proline plays a significant role in plant resistance to abiotic stresses, and its level is determined by a combination of synthesis, catabolism and transport. The primary proteins involved are Δ1-pyrroline-5-carboxylate synthetase (P5CS), proline dehydrogenase (PDH) and proline transporter (ProT). To utilise proline metabolism to improve the stress resistance of Chrysanthemum × morifolium, we isolated two P5CS-homologous genes (ClP5CS1 and ClP5CS2), one PDH gene (ClPDH) and four ProT-homologous genes (ClProT1-4) (GenBANK accession numbers: KF743136–KF743142) from Chrysanthemum lavandulifolium, which is closely related to chrysanthemums and exhibits strong resistance to stresses. Expression analysis of these genes in different organs and under various stresses indicated that ClP5CSs showed substantial constitutive expression, while ClPDH was only strongly expressed in the capitulum and was inhibited under most stresses. The expression patterns of four ClProT genes presented characteristics of organ specificity and disparity under stresses. Above all, the expression of ClProT2 was restricted to above-ground organs, especially strong in the capitulum and could be obviously induced by various stress conditions. Promoters of ClPDH and ClProTs contained many cis-acting regulatory elements involved in stress responses and plant growth and development. High levels of free proline were found in flower buds, the capitulum under the non-stress condition and later periods of stress conditions except cold treatment. Interestingly, organ specificity and disparity also exist in the level of free proline under different stress conditions. Our study indicates that ClProTs play significant roles in proline accumulation and stress responses, and that ClProT2 could be used to genetically modify the stress resistance of chrysanthemums. In addition, proline metabolism might be closely related to plant flowering and floral development. 相似文献
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Zun-Zheng Wei Lai-Bo Luo Hua-Li Zhang Min Xiong Xian Wang Di Zhou 《American journal of botany》2012,99(12):e493-e497
• Premise of the study: A new set of microsatellite or simple sequence repeat (SSR) markers from expressed sequence tags (ESTs) was developed for arum lily (Zantedeschia aethiopica), which is one of the most iconic and widely recognized ornamental plants in the world. • Methods and Results: Using 2175 unigenes derived from 4283 random ESTs in arum lily, 166 primer pairs were designed and tested for amplification in 24 accessions from Asia, Europe, and Africa. A total of 43 loci were polymorphic, with the number of alleles per locus ranging from two to 10. The observed heterozygosity, expected heterozygosity, and polymorphism information content ranged from 0.2313 to 0.8480, 0.3034 to 0.8648, and 0.1015 to 0.7364, respectively. • Conclusions: These novel polymorphic EST-SSR markers will facilitate future studies of genetic variation and molecular-assisted breeding systems in arum lily. 相似文献
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Apple (Malus domestica Borkh.), an important horticultural crop, produces human health-promoting metabolites during fruit ripening. Because that
process, which involves complex biochemical and physiological changes, is genetically programmed, molecular and genetic approaches
have been taken to understand the associated cellular mechanisms. The release of 151,687 apple expressed sequence tags (ESTs)
into a public database has made possible large-scale studies of expression. Analysis of apple ESTs allows for the identification
and characterization of genes with potential roles in fruit development, particularly those related to aroma production and
protein degradation during ripening. Apple cDNA and oligonucleotide microarrays have been generated for more comprehensive
examinations. Such tools are powerful means for elucidating the molecular events involved in metabolite biosynthesis and physiological
changes and will also enable researchers to understand how to control that ripening process. 相似文献
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Joonyul Kim Sung-Hoon jun Jinwon Lee Hong-Gyu Rang Gynheung An 《Journal of Plant Biology》2001,44(3):172-177
To understand the molecular events that occur during reproductive organ development and to provide genetic resources for molecular
breeding, we generated 328 expressed sequence tags (ESTs) from randomly selected clones of four watermelon cDNA libraries.
These libraries were prepared from young and mature anthers, as well as the seed coat and inner seed tissues. EST clones found
in the young anthers and inner seed tissues showed similarity with genes related to development and signal transduction. We
could deduce that, especially in the developing inner seed tissues, important morphological processes were associated exclusively
with seed and embryo development In addition, seed metabolism was tailored toward the accumulation of economically valuable
storage compounds such as lipids. In the seed coat, EST clones showed similarity with genes that influence the transport or
conversion of nutrients such as porin, sucrose synthase, L-asparaginase, and arginine decarboxylase. We also selected two
cDNA clones from each of the four classes of ESTs for studying expression levels and patterns in the various organs. Among
those eight clones, three (An88, Is124, and Sc68) were expressed preferentially in their particular organ. 相似文献
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T Morio H Urushihara T Saito Y Ugawa H Mizuno M Yoshida R Yoshino B N Mitra M Pi T Sato K Takemoto H Yasukawa J Williams M Maeda I Takeuchi H Ochiai Y Tanaka 《DNA research》1998,5(6):335-340
In an effort to identify and characterize genes expressed during multicellular development ill Dictyostelium, we have undertaken a cDNA sequencing project. Using size-fractionated subsets of cDNA from the first finger stage, two sets of gridded libraries were constructed for cDNA sequencing. One, library S, consisting of 9984 clones, carries relatively short inserts, and the other, library L, which consists of 8448 clones, has longer inserts. We sequenced all the selected clones in library S from their 3'-ends, and this generated 3093 non-redundant, expressed sequence tags (ESTs). Among them, 246 ESTs hit known Dictyostelium genes and 910 showed significant similarity to genes of Dictyostelium and other organisms. For library L, 1132 clones were randomly sequenced and 471 non-redundant ESTs were obtained. In combination, the ESTs from the two libraries represent approximately 40% of genes expressed in late development, assuming that the non-redundant ESTs correspond to independent genes. They will provide a useful resource for investigating the genetic networks that regulate multicellular development of this organism. 相似文献