Saturday, July 9, 2011

Genome regulatory elements: CCMB finding helps in gene therapy and making transgenic animals and plants effective

Syed Akbar
Hyderabad: Scientists at the city-based Centre for Cellular and Molecular Biology have found genome regulatory elements that can help in effective and successful introduction of genes from external sources into an organism. These regulatory elements are conserved during evolution and form part of the mechanism involving gene therapy and making transgenic animals and plants.
Gene therapy, which is likely to emerge as a major frontier of medical science in near future, has its drawbacks too. But the findings of the CCMB team headed by Dr Rakesh K Mishra may help in overcoming these drawbacks to make gene therapy really reliable in treating genetic diseases, for which there's no cure at present. There are a number of diseases for which gene therapy is the only hope.
In gene therapy, defective genes are corrected by introducing functional genes in the patient body. In many cases though the gene therapy solves the identified problem, it leads to emergence of new health issues. Some times this is because the genomic context in which new gene is inserted leads to inappropriate interactions of the genetic material in the vicinity.
The CCMB team has noticed that there exists "boundary elements", which divide the genomic information into different compartments so as to avoid unwanted disturbance or cross-talk.
Thanks to these boundary elements, even if a new gene is inserted to replace a defective gene, the genetic information in the region does not get troubled. This mechanism works across the species in plants and animals, ranging from the simple Drosophila to the complex human beings.
"Our finding has significant advantage to gene therapy and development of transgenic plants and animals. In gene therapy it will protect the gene which we insert from being mis-regulated. It will also help in making transgenic plants and animals more regulated by reducing undesired features, which crop up due to accidental misregulation. Whatever you want to make will be more effective and less disturbed," said Dr Rakesh Mishra.
Dr Mishra's team followed "Hox genes" that determine which part of the fertilised egg mass to develop into which body part. They help in providing proper shape to the body, whether insect or mammal, including formation of the organs and positioning them in order.
"In vertebrates, distinctly expressed Hox genes are closely spaced. This raises the possibility of boundary elements being present in the intergenic locations to mark the regulatory features of each gene, in a manner similar to Drosophila homeotic gene regulation. The Evx2-Hoxd13 region in the mouse HoxD complex is one such example where two differentially expressed genes are separated by about 9 kb of intervening DNA, he added. These findings have been published in the prestigious international journal ‘Development’ recently.

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