共查询到20条相似文献,搜索用时 15 毫秒
1.
V Rait D Sergueev J Summers K He F Huang B Krzyzanowska B R Shaw 《Nucleosides & nucleotides》1999,18(6-7):1379-1380
Important chemical and biochemical properties of boranophosphate DNA and RNA oligonucleotides are reviewed. Stereoregular boranophosphate oligomers can be synthesized enzymatically and form stable duplexes with DNA. Fully boronated, non-stereoregular oligothymidylates, synthesized chemically, form hybrids with poly(A) that have lower melting points than oligothymidylate:poly(A), yet they nevertheless can support the RNase H mediated cleavage of RNA. 相似文献
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Enya Y Nagata S Masutomi Y Kitagawa H Takagaki K Oka N Wada T Ohgi T Yano J 《Bioorganic & medicinal chemistry》2008,16(20):9154-9160
We have synthesized diastereomerically pure diadenosine 3',5'-boranophosphates (Ap(b)A) by using the boranophosphotriester method from ribonucleosides protected with the 2'-hydroxy protecting group 2-cyanoethoxymethyl (CEM). Melting curves of the triple-helical complex of the dimer Ap(b)A and 2poly(U) at high ionic strength revealed that presumptive (Sp)-Ap(b)A had a much higher affinity and presumptive (Rp)-Ap(b)A a much lower affinity for poly(U) than the natural dimer ApA did. In contrast, the affinities of these dimers for poly(dT) were similar. Both the (Rp)- and the (Sp)-boranophosphate diastereomers showed much higher resistance to digestion by snake venom phosphodiesterase and nuclease P1 than ApA did. They have potential for use as synthons to be incorporated into boranophosphate oligonucleotides. In particular, because oligonucleotides containing Sp boranophosphate nucleotides are expected to bind more strongly and specifically to RNA than natural oligoribonucleotides do, they may find application in the isolation and detection of functional RNA in basic research and diagnostics. 相似文献
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Pierre Kerjan Kunthala Jayaraman Jekisiel Szulmajster 《Molecular & general genetics : MGG》1982,185(3):448-453
Summary cDNA probes synthesized on poly(A)RNAs isolated from sporulating cells of Bacillus subtilis were used for hybridization studies with RNAs derived from cells at different stages of growth and sporulation. It was shown that these cDNAs hybridized only to RNA from sporulating cells. No hybridization was observed if total RNA isolated from vegetative cells or from stationary phase cells of a zero stage asporogenic mutant was used. The hybridization studies also indicate that at each sporulation stage different poly(A)RNA species are synthesized. Furthermore, the hybridization kinetics have clearly demonstrated the existence of three distinct abundance classes of poly(A)RNA similar to those observed in eukaryotic cells.
BamHI endonuclease restriction fragments of B. subtilis DNA that were found to hybridize to labeled poly(A)RNA were ligated to the pHV33 vector and hybrid clones that hybridized efficiently to poly(A)RNA were selected. Among these, three have been found to carry the spoOB gene.These results strongly suggest that the appearance of poly(A)RNA can be correlated to the expression of spore genes. 相似文献
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Dmitri Sergueev Ahmad Hasan Muthukumar Ramaswamy Barbara Ramsay Shaw 《Nucleosides, nucleotides & nucleic acids》2013,32(7-9):1533-1538
Abstract Recently our laboratory reported a new backbone-modified class of oligonucleotides, with a borane (B33?) group replacing one of the non-bridging oxygen atoms. Here we present two new approaches to synthesize the boranophosphate oligonucleotides. All-stereoregular boranophosphate oligonucleotides can be prepared by enzymatic template extension reactions using nucleoside a-boranotriphosphates, which are good substrates for a number of polymerases. Larger scale synthesis of boranophosphate oligonucleotides can be carried out by effective chemical synthesis using the H-phosphonate approach, instead of previously used phosphoramidite methodology. The main advantage of H-phosphonate methodology is the ability to carry out one boronation reaction, after oligonucleotide chain elongation has been completed, using mild conditions without base damage and producing the desired boranophosphate oligonucleotides in high yield. 相似文献
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Abstract A cDNA library derived from poly(A)+RNA of bull seminal vesicle- tissue was screened with a synthetic DNA hybridisation probe specific for the major protein of bull semen. A positive clone pMP17, containing a 680 bp insert, was sequenced. In combination with primer extension sequencing of poly(A)+RNA, a DNA sequence of 700 bp was determined. This DNA encoded a reading frame for 134 amino acids, starting with an ATG and terminated by a TAG codon. This comprised 25 amino acids of a signal peptide followed by 109 amino acids with the known sequence of the major protein. 相似文献
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Yohei Koga Yosuke Taniguchi Shigeki Sasaki 《Nucleosides, nucleotides & nucleic acids》2013,32(3):124-136
6-O-7-N-Bis(diphenylcarbamoyl)-2-N-phenoxyacetyl-5′-O-dimethoxytrityl-2′-O-{[(triisopropyl- silyl)oxy]methyl}-8-oxoguanosine-3′-yl-β-cyanoethyl-N,N-diisopropylphosphoramidite (5) was synt- hesized as a new phosphoramidite precursor unit for the synthesis of RNA. Compound 5 was successfully incorporated into the middle of the RNA sequences, and the synthesized RNAs were identified by MALDI-TOF mass measurements. Their properties were evaluated for formation of the RNA duplex and RNA/DNA heteroduplex. ORNs 1 and 4 containing 8-oxo-G can form base pairs with rC or dC in an anti conformation, while it can also interact with rA or dA in a syn conformation in the RNA duplex or RNA/DNA heteroduplex. The described synthetic method is therefore a useful procedure for the synthesis of ORN containing 8-oxo-G and contributes to the study of 8-oxo-G in RNA. 相似文献
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Summary Nuclear poly(A)+ and polysomal poly(A)+ RNA were isolated from gastrula and early tadpole stages of the amphibianXenopus laevis. Complementary DNA was synthesized from all RNA preparations. Hybridization reactions revealed that at least all abundant and probably most of the less frequent nuclear and polysomal poly(A)+ RNA species present at the gastrula stage are also present at the early tadpole stage. On the other hand, there are nuclear RNA sequences at the latter stage which appear, if at all, only at lower concentrations at the gastrula stage. The polysomal poly(A)+ RNA hybridization reactions suggest the existence of polysomal poly(A)+ RNA sequences at early tadpole stages which are not present in the corresponding gastrula stage RNA.By cDNA hybridization with poly(A)– RNA it could be shown that most of the poly(A)+ containing RNA sequences transcribed into cDNA were also present within the poly(A)– RNA. It was estimated, that these sequences are 10 fold more abundant within the poly(A)– polysomal RNA and 3–6 more abundant within the poly(A)– nuclear RNA as compared to the poly(A)+ RNAs. 相似文献
10.
H. Lorberboum D. Weinstein H. Galski N. de Groot S. Segal J. Ilan R. Folman A. A. Hochberg 《Molecular biology reports》1982,8(2):103-110
The in vitro synthesis of RNA in the human placental tissue, incubated in organ culture, was investigated. We followed the synthesis of the poly A(-) and poly A(+) RNA fractions, and investigated the distribution of the newly synthesized RNA among the subcellular fractions isolated from first and third trimester placentas.The poly A(-) RNA was the major fraction of the RNA synthesized in vitro. The incorporation of [3H]uridine into the poly A(+) RNA fraction was very low.As protein synthesis occurred during the entire incubation period, we suggest the presence of a pool of mRNA molecules in the form of mRNP particles. 相似文献
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Abstract We have studied by X-ray diffraction fibers of complexes of poly(dG)·poly(dC) with N-α-acetyl-L-arginine ethylamide. Although these polynucleotides favour the A form of DNA, in this complex it is never found, thus confirming that arginine prevents the appearance of this form of DNA At high relative humidity the B form is present. Upon dehydration two new structures appear. One of them is a triple helix, most likely formed by poly(dC+) · poly(dG) · poly(dC). The other structure found also has features which indicate a multistranded conformation. 相似文献
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Changing rates of DNA and RNA synthesis in Drosophila embryos 总被引:6,自引:0,他引:6
Rates of DNA and RNA synthesis during Drosophila embryogenesis were measured by labeling octane-treated embryos with [14C]thymidine and [3H]uridine. Radioactivity incorporated per hour was converted to rates of synthesis using measurements of the pool-specific activity during the labeling periods. The rate of DNA synthesis during early embryogenesis increases to a maximum at 6 hr after oviposition and then decreases sharply. Measured rates of DNA synthesis were used to calculate that the total amount of DNA per embryo doubles every 18 min at blastoderm, every 70–80 min during gastrulation, and less than once every 7 hr at later stages. The rate of RNA accumulation per embryo increases continuously during the first 14 hr of embryogenesis. The rate of nuclear RNA synthesis per diploid amount of DNA, however, decreases fivefold between blastoderm and primary organogenesis. The cytoplasmic poly(A)+ RNA synthesized by blastoderm embryos associates rapidly with polysomes. The relatively high rate of synthesis of polysomal poly(A)+ RNA per nucleus at blastoderm allows the small number of nuclei present at blastoderm to make a significant quantitative contribution to the informational RNA active in the early embryo. At the end of blastoderm, approximately 14% of the mRNA being translated in the embryo has been synthesized after fertilization. 相似文献
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Paul S. Miller Purshotam Bhan Lou-Sing Kan 《Nucleosides, nucleotides & nucleic acids》2013,32(8):785-792
Abstract Oligodeoxyribonucleotides containing 2′-amino-2′-deoxy-uridine (dU) were synthesized and their ability to form duplexes with complementary DNA or RNA oligonucleotides was studied. Substitution of dU with dU in these oligomers results in lowered Tms of the duplexes. 相似文献
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Synthesis of DNA from Vaccinia Messenger RNA Templates 总被引:3,自引:0,他引:3
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By hybridization with [3H]labeled globin cDNA the contents of globin coding sequences in total nuclear RNA, poly(A)+nuclear RNA, poly(A)--nuclear RNA and polysomal RNA of chicken immature red blood cells was determined to be 0.86%, 20%, 0.42% and 1% respectively. As the poly(A)+-fraction comprises only about 2% of total nuclear RNA, globin coding sequences are distributed with 49% in the poly(A)+-fraction and with 51% in the poly(A)--fraction.Part of the mRNA sequences which are found in liver are also transcribed in immature red blood cells. These sequences are enriched in poly(A)+-nuclear RNA as the globin coding sequences but their total amount in the poly(A)+-fraction is much smaller than in the poly(A)--fraction.When nuclear RNA from immature red blood cells was translated in an ascites tumor cell-free system, 20% of the newly synthesized proteins were globin chains. The percentage of globin chains in the newly synthesized proteins increased to over 70% when poly(A)+-nuclear RNA was translated. Only about 7.5% of globin chains were found in proteins coded by poly(A)--nuclear RNA. 相似文献
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Alex Andrus Ravi Vinayak Robert G. Kuimelis Bashar Mullah 《Nucleosides, nucleotides & nucleic acids》2013,32(7-9):1183-1194
Abstract A series of 2′-O-methyl RNA/DNA chimera oligonucleotides were synthesized with a double-hairpin structural motif. Liposome formulated delivery of the chimeras effected targeted, high conversion of mutant alleles in mammalian cell culture. The chimera oligonucleotides were prepared with DNA and 2′-OMe RNA phosphoramidite nucleoside monomers on the ABI 394 synthesizer. 相似文献
20.
Mats Ola Nilsson Tore Hultin 《Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression》1982,696(3):253-259
Encysted embryos of Artemia contain latent mRNA, to a large extent associated with a fraction of cytoplasmic membranes. The membranes, purified by EDTA treatment and banding in a sucrose gradient at 1.17 g/cm3, include endoplasmic vesicles and mitochondria. The origin of the membrane-associated poly(A)+RNA was therefore investigated. In gel electrophoresis poly(A)+RNA from the purified membranes of dormant cysts forms two distinct bands at approx. 3·105 and 5·105 Da. Later during development the lighter component decreases. Nuclei from dormant cysts are devoid of poly(A)+RNA, while nuclei from developing embryos (50% emergence) contain a predominant poly(A)+RNA component of approx. 5·105 Da. 125I-labelled preparations of nuclear DNA and of nuclear and membrane-associated poly(A)+RNA were used in reassociation and hybridization experiments with excess nuclear DNA. Poly(A)+RNA from the membranes of dormant cysts hybridized to nuclear DNA to the same extent as the nuclear poly(A)+RNA from developing embryos. The hybridization of labelled, nuclear poly(A)+RNA to nuclear DNA was strongly inhibited by unlabelled membrane RNA from either dormant cysts or developing embryos. It is concluded that the stored, membrane-associated poly(A)+RNA in dormant cysts is essentially of nuclear origin. The 5·105-Da component is largely homologous with the corresponding component of nuclear poly(A)+RNA at later stages. 相似文献