Wyniki wyszukiwania

1

Rekombinacja RNA w układzie wirus-roślina transgeniczna - ryzyko powstania nowego wirusa

100%

Urbanowicz A., Alejska M., Figlerowicz M., Bujarski J. J.

Biotechnologia

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2003

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nr 2

2

Homologous RNA recombination as a factor stabilizing and destabilizing a viral genome

100%

Urbanowicz A., Alejska M., Figlerowicz M., Bujarski J.

Acta Biochimica Polonica

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2003

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tom 50

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nr Supplement 1

3

Two types of non-homologous RNA recombination in brome mosaic virus

100%

Alejska M., Malinowska N., Urbanowicz A., Figlerowicz M.

Acta Biochimica Polonica

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2005

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tom 52

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nr 4

Non-homologous RNA recombination is a process enabling the exchange of genetic material between various (related or unrelated) RNA-based viruses. Despite extensive investigations its molecular mechanism remains unclear. Studies on genetic recombination in brome mosaic virus (BMV) have shown that local hybridization between genomic RNAs induces frequent non-homologous crossovers. A detailed analysis of recombinant structures suggested that local complementary regions might be involved in two types of non-homologous recombination in BMV: site-specific and heteroduplex-mediated. To verify the above hypothesis and better recognize the mechanism of the phenomenon studied we have tested how the putative types of recombination are affected by a specific mutation in the BMV polymerase gene or by changes in RNA structure. The experiments undertaken revealed substantial differences between site-specific and heteroduplex-mediated recombination, indicating that they occur according to different mechanisms. The former can be classified as homology-assisted, and the latter as homology-independent. In addition to local RNA/RNA hybridization, short regions of homology are required for site-specific crossovers to occur. They are most efficiently mediated if one homologous sequence is located at the beginning of and the second just before a double-stranded region. At present it is difficult to state what is the mechanism of heteroduplex-mediated recombination. Earlier it was postulated that strong RNA/RNA interaction enforces template switching by the viral replicase. There are, however, several observations questioning this model and indicating that some other factors, which are still unknown, may influence heteroduplex-mediated crossovers.

4

Low recombination activity of R region located at both ends of the HIV-1 genome

88%

Urbanowicz A., Kurzynska-Kokorniak A., Jankowska A., Alejska M., Figlerowicz M.

Acta Biochimica Polonica

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2012

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tom 59

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nr 4

Although two strand transfer events are indispensable for the synthesis of double-stranded DNA and establishing HIV-1 infection, the molecular basis of these phenomena is still unclear. The first obligatory template switching event occurs just at the beginning of the virus replication cycle and involves two copies of the 97-nucleotide long R region, located one each at the both ends of the HIV-1 genome (HIV-1 R). Thus, one can expect that the molecular mechanism of this process is similar to the mechanism of homologous recombination which operates in RNA viruses. To verify the above-mentioned hypothesis, we attempted to assess the recombination activity of HIV-1 R. To this end, we tested in vitro, how effectively it induces template switching by HIV-1 RT in comparison with another well-characterized sequence supporting frequent homologous crossovers in an unrelated virus (R region derived from Brome mosaic virus - BMV R). We also examined if the RNA sequences neighboring HIV-1 R influence its recombination activity. Finally, we tested if HIV-1 R could cause BMV polymerase complex to switch between RNA templates in vivo. Overall, our results have revealed a relatively low recombination activity of HIV-1 R as compared to BMV R. This observation suggests that different factors modulate the efficiency of the first obligatory strand transfer in HIV-1 and the homology-driven recombination in RNA viruses.

5

How RNA viruses exchange their genetic material

88%

Alejska M., Kurzynska-Kokorniak A., Broda M., Kierzek R., Figlerowicz M.

Acta Biochimica Polonica

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2001

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tom 48

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nr 2

One of the most un usual fea tures of RNA vi ruses is their enor mous ge netic vari ability. Among the dif fer ent pro cesses con trib ut ing to the con tin u ous gen er a tion of new vi ral vari ants RNA re com bi na tion is of spe cial im por tance. This pro cess has been observed for human, animal, plant and bacterial viruses. The collected data reveal a great sus cep ti bil ity of RNA vi ruses to re com bi na tion. They also in di cate that ge netic RNA re com bi na tion (es pe cially the nonhomologous one) is a major fac tor re spon si ble for the emer gence of new vi ral strains or spe cies. Al though the for ma tion and ac cu mu la tion of vi ral recombinants was ob served in numer ous RNA vi ruses, the mo lec u lar ba sis of this phe nom e non was stud ied in only a few vi ral spe cies. Among them, brome mo saic vi rus (BMV), a model (+)RNA vi rus offers the best op por tu ni ties to in ves ti gate var i ous as pects of ge netic RNA re com bi nation in vivo. Unlike any other, the BMV-based system enables homologous and nonhomologous re com bi na tion stud ies at both the pro tein and RNA lev els. As a con sequence, BMV is the vi rus for which the struc tural re quire ments for ge netic RNA re- com bi na tion have been most pre cisely es tab lished. Nev er the less, the pre vi ously proposed model of ge netic re com bi na tion in BMV still had one weak ness: it could not really ex plain the role of RNA struc ture in nonhomologous re com bi na tion. Re cent discoveries concerning the latter problem give us a chance to fill this gap. That is why in this re view we pres ent and thor oughly dis cuss all re sults con cern ing nonhomologous recombination in BMV that have been ob tained un til now.

6

RNAi and viral vectors as useful tools in the functional genomics of plants. Construction of BMV-based vectors for RNA delivery into plant cells

76%

Wojtkowiak A., Siek A., Alejska M., Jarmolowski A., Szweykowska-Kulinska Z., Figlerowicz M.

Cellular and Molecular Biology Letters

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2002

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tom 07

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nr 2A

The sequencing of several complete genomes and the development of a DNA microarray technology are among the most important achievements of molecular biology. They gave the proper grounds for the development of modern functional genomics. However, there is one additional condition which needs to be satisfied to truely enable the study of how a genome works: a suitable method of selectively inducing and silencing the expression of each individual gene. The methods used so far have usually only permitted the influfencing of gene expression through genetic manipulations at the DNA level (genetically modified plants). The discovery of RNA interference (RNAi) opens up completely new possibilities of research on the functioning of particular plant genes, without the necessity of altering the genome structure. In this case, interference takes place at the transcript level. Thus, at any given moment during plant development, the expression of a specific gene (or several genes) can be inhibited, even if it is important for the survival of the organism under study. To this end, a double-stranded RNA inducing the RNAi phenomenon has to be delivered into the plant cell. Here we describe the construction of four brome mosaic virus-based vectors, which, as our preliminary data indicate, can be used to transfer RNA into barley cells.

7

Identification of the factors responsibile for generation of hepatitis C virus variants resistant to antiviral treatment

76%

Jackowiak P., Figlerowicz M., Alejska M., Kedziora P., Formanowicz P., Blazewicz J., Figlerowicz M.

Acta Biochimica Polonica

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2006

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tom 53

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nr Supplement 1

8

Brome mosaic virus [BMV] and barley stripe mosaic virus [BSMV] - based vectors: application in gene silencing in plants

64%

Barciszewska-Pacak M., Pacak A., Florek B., Alejska M., Lacomme C., Szweykowska-Kulinska Z., Figlerowicz M., Jarmolowski A.

Biological Letters

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2005

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tom 42

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nr 2 Spec.Vol.

Ograniczanie wyników

Rekombinacja RNA w układzie wirus-roślina transgeniczna - ryzyko powstania nowego wirusa

Homologous RNA recombination as a factor stabilizing and destabilizing a viral genome

Two types of non-homologous RNA recombination in brome mosaic virus

Low recombination activity of R region located at both ends of the HIV-1 genome

How RNA viruses exchange their genetic material

RNAi and viral vectors as useful tools in the functional genomics of plants. Construction of BMV-based vectors for RNA delivery into plant cells

Identification of the factors responsibile for generation of hepatitis C virus variants resistant to antiviral treatment

Brome mosaic virus [BMV] and barley stripe mosaic virus [BSMV] - based vectors: application in gene silencing in plants