Search results

1

Transfer and transgene expression

100%

Szopa J., Wrobel M.

Biotechnologia

|

2001

|

issue 1

63-72

EN

The development of transgenic plants strongly depends on the stable introduction of foreign nucleic acid into the plant genome. Recently, various transformation methods have been developed and successfully used for the development of transgenic plants of agricultural importance. Various vectors have been prepared, however the binary vector based on agrobacterial T-DNA is most commonly used. Of vectorless gene transfer systems, particle bombardment seems to be most useful. In both approaches, stable integration of DNA is based on random hybridization. The transformation efficiency is measured by the level of transgene expression and it may be potentially improved by different modifications, including insertion of multiple copies of promoter into a particular gene, insertion of procaryotic enhancer, increasing of mRNA stability, insertion of SAR/MAR sequences at the ends of gene, etc. Very recently it has been found that the increase of histone synthesis enhances transgene expression possibly as a result of increased transformation efficiency. Transgenic plants production also depends on the efficiency of the plant regeneration system which is used. There is no universally applicable method for regeneration of different tissues from various sources, thus regeneration protocol should be modified appropriately for each tissue and species.

2

The transgenes are expressed with different level in plants

100%

Yin Z., Malepszy S.

|

EN

Variable expression for the same transgene construct has been documented in various plant species, regardless of the type of transgene. This phenomenon and the factors influencing it are reviewed. A variability in the transgene expression level was found to exist between and/or within independently derived lines, different lines of clonal replicates, siblings of the same line, a single plant, a single leaf as well as the same cell. Both the transgene dependent and the recipient dependent factors have been proposed to account for this phenomenon, the transgene dependent factors of which include transgene construct fidelity, T-DNA integration pattern, T-DNA copy number, promoter activity and the effect of nuclear matrix attachment region. In addition, different forms of epigenetic, homology-dependent gene silencing also contribute to the unstable expression of the identical transgene. The recipient dependent factors include position effect, ploidy level, genetic background, homozygosity, and developmental stage. Furthermore, environmental factors such as light intensity, temperature, field growth conditions and the season have been shown to modulate the levels of transgene expression. The approaches to stabilize the transgene expression were also discussed.

3

Expression pattern of the pre-prothaumatin II gene under the control of the CaMV 35S promoter in transgenic cucumber (Cucumis sativus L.) flower buds and fruits

75%

Szwacka M., Siedlecka E., Zawirska-Wojtasiak R., Wisniewski L., Malepszy S.

Journal of Applied Genetics

|

2009

|

vol. 50

|

issue 1

9-16

EN

Thaumatin II is an extremely sweet-tasting protein produced by fruits of the West African shrub Thaumatococcus daniellii Benth, so it can be used in biotechnology to improve the tastes of various plant products. This study is concerned with the spatial and temporal aspects of expression of the 35S-pre-prothaumatin II chimeric gene in flower buds and fruits of transgenic cucumber (Cucumis sativus L.) line 225. The activity of the 35S promoter in organs of line 225 was compared with its activity in 2 other transgenic lines. The accumulation of recombinant thaumatin varied spatially in flower bud tissues of transgenic lines. We found that these differences in the spatial accumulation of transgenic protein concerned the ovary of female buds and the perianth of male buds. In contrast to flower parts, recombinant thaumatin was found in nearly all parts of the young fruit from the transgenic plants. The pre-prothaumatin II gene expression was detected at a very early developmental stage in male buds, and its pattern was rather conserved as the buds aged. The expression of the transgene was also detected in vascular tissues of examined organs but was undetectable in pollen grains, in agreement with the generally held view that the CaMV 35S promoter is virtually silent in pollen. Immunocytochemical analyses of sections of control organs revealed endogenous homolog(s) of thaumatin when using polyclonal antisera, but not when using monoclonal antibodies for recombinant thaumatin detection in transgenic cucumber.

Refine search results

2 Biotechnologia

1 Journal of Applied Genetics

1 2009

1 2003

1 2001

2 Malepszy S.

1 Siedlecka E.

1 Szopa J.

1 Szwacka M.

1 Wisniewski L.

1 Wrobel M.

1 Yin Z.

1 Zawirska-Wojtasiak R.

Transfer and transgene expression

The transgenes are expressed with different level in plants

Expression pattern of the pre-prothaumatin II gene under the control of the CaMV 35S promoter in transgenic cucumber (Cucumis sativus L.) flower buds and fruits