Transfer i regulacja ekspresji transgenu

The development oftransgenic 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 havebeen prepared, however the binary vector based on agrobacterial T-DNA ismost commonly used. Of vectorless gene transfer systems, particle bombardment seems to be most useful. In both approaches, stable integration of DNA isbased on random hybridization. The transformation efficiency is measured bythe level of transgene expression and it may be potentially improved by different modifications, including insertion of multiple copies of promoter into aparticular gene, insertion of procaryotic enhancer, increasing of mRNA stability,insertion of SAR/MAR sequences at tbe ends of gene, etc. Very recently it hasbeen found that the increase of histone synthesis enhances transgene expressionpossibly as a result of increased transformation efficiency. Transgenic plantsproduction also depends on the efficiency of the plant regeneration systemwhich is used. There is no universally applicable method for regeneration ofdifferent tissues from various sources, thus regeneration protocol should bemodified appropriately for each tissue and species.