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Wyświetlanie 1-3 z 3
Tytuł:
Effect of nuclear matrix attachment regions on transgene expression in tobacco plants.
Autorzy:
Nowak, Witold
Gawłowska0, Magdalena
Jarmołowski, Artur
Augustyniak, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/1044093.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
plant transformation
matrix attachment region
transgene expression
Opis:
Matrix attachment regions (MARs) are thought to participate in the organization and segregation of independent chromosomal loop domains. Although there are several reports on the action of natural MARs in the context of heterologous genes in transgenic plants, in our study we tested a synthetic MAR (sMAR) with the special property of unpairing when under superhelical strain, for its effect on reporter gene expression in tobacco plants. The synthetic MAR was a multimer of a short sequence from the MAR 3' end of the immunoglobulin heavy chain (IgH) enhancer. This sMAR sequence was used to flank the β-glucuronidase (GUS) reporter gene within the T-DNA of the binary vector pBI121. Vectors with or without the sMARs were then used to transform tobacco plants by Agrobacterium tumefaciens. Transgenic plants containing the sMAR sequences flanking the GUS gene exhibited higher levels of transgene expression compared with transgenic plants which lacked the sMARs. This effect was observed independently of the position of the sMAR at the 5' side of the reporter gene. However, variation of the detected transgene expression was significant in all transformed plant populations, irrespective of the construct used. Most genes whose expression has been studied in transgenic plants are generally expressed in appropriate patterns. However, transgene expression can vary within an extremely wide range, often showing only a very low level [1, 2]. Variation in transgene expression is frequently attributed to corresponding variation in the transcription potential of different chromosomal insertion sites. DNA sequences called scaffold/matrix attachment regions (S/MARs) are involved in the structural and functional organization of all eukaryotic genomes. Evolutionarily, the structures of these sequences seem to be conserved. Typically, S/MARs are located every 5 to 200 kb of sequence and are known to bind specifically to components of the nuclear scaffold, therefore suggesting that they are responsible for loop domain base formation [3, 4].Of the MAR elements reported, many do not display extensive sequence homology. It is therefore reasonable to assume that the scaffold probably recognizes some structural features of the MAR DNA rather than a specific sequence [5].MARs appear to be functionally conserved, since animal MARs can bind to plant nuclear scaffolds and vice versa [6, 7].Most MARs have been generally characterized as AT-rich sequences. However, AT-richness per se is not a sufficient criterion for specific sequence recognition of MARs by specific binding proteins [7]. Their capacity to bind to the nuclear matrix is determined by the specific structure of DNA. A prominent structural characteristic of different MARs is their strong potential for extensive unpairing when subjected to superhelical strain [8, 9]. The ability to assume a stably unpaired conformation has been described for several MARs. For example, within the MAR 3' end of immunoglobulin heavy chain (IgH) enhancer there is an AATATATTT motif that is a nucleation site for DNA unwinding [10]. Concatamerized oligonucleotides containing seven repeats of this sequence exhibited a strong affinity for the nuclear scaffold and increased SV40 promoter activity in stably transformed mouse cells [11].In this paper we present results of our studies that concern the effect of a synthetic MAR on transgene expression in tobacco plants. The synthetic MAR sequences were used to flank the β-glucuronidase (GUS) gene whose transcription was under control of the 35S CaMV promoter in the binary vector pBI121. This construct was introduced into tobacco plants and the GUS reporter gene expression was monitored in stably transformed plants.
Źródło:
Acta Biochimica Polonica; 2001, 48, 3; 637-646
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Beta-actin in human colon adenocarcinoma cell lines with different metastatic potential.
Autorzy:
Nowak, Dorota
Skwarek-Maruszewska, Aneta
Zemanek-Zboch, Magdalena
Malicka-Błaszkiewicz, Maria
Powiązania:
https://bibliotekanauki.pl/articles/1041430.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
actin cytoskeleton
β-actin
colon adenocarcinoma
invasiveness
Opis:
Human colon adenocarcinoma LS180 parental cell line and selected variants, characterized by different metastatic capacity were used to examine, whether a correlation exists between β-actin expression, its subcellular distribution and metastatic potential of these cells. Cytosolic fraction (supernatant 105000 × g), isolated from the tumor cells was used as a source for actin quantification. The higher level of β-actin was observed in the cytosol of three selected sublines to compare with LS180 parental line. Statistically significant increase of β-actin level in highly motile EB3 cells variant should be underlined to compare with the other sublines. Distinct differences in the phenotype of adenocarcinoma cell variants were found, such as the changes in cells shape, cells spreading and ability to attach to the surface of culture dish. Actin cytoskeleton was visualized with fluorescence microscopy application and microfilaments rhodamine-conjugated phalloidin staining. β-actin subcellular localization was done by immunofluorescence staining with monoclonal anti-β actin antibodies. In the elongated cells (LS180, 3LNLN), this isoactin is dispersed in the whole cell body and concentrates in pseudopods and at the leading edges, when in the rounded variant (EB3) β-actin dominates mainly in cortical ring under cellular membrane and it is also seen in the subtle protrusions. Summary of our former (Nowak et al., 2002, Acta Biochim. Polon., 49: 823) and current data lead to the conclusion that there is a distinct correlation between metastatic capacity of examined human colon adenocarcinoma cells, the state of actin polymerization, actin cytoskeleton organization and β-actin expression.
Źródło:
Acta Biochimica Polonica; 2005, 52, 2; 461-468
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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