Genetic manipulation is an inherent part of molecular biology and scientists use various methods gene manipulation methods in their day to day research. But, not all methods are as precise and effective as transcription-activator-like-effector (TALE) based techniques, and they just became more effective following a breakthrough achieved by researchers at The Scripps Research Institute.
The designer TALE proteins used for gene activation, inactivation, insertion, deletion and rewriting specific genes are designed based on naturally occurring TALE proteins produced by some bacteria that infect plants to help them subvert the hosts by binding to specific sites on plant DNA to boost the activity of certain genes, ensuring growth and survival of the bacteria. All naturally occurring TALE proteins are found to target the DNA sequences having thymidine as the beginning of transcription sequence, and the same was assumed in the case of artificial designer TALE proteins as well.
The Scripps Research Institute team, led by Professor Carlos Barbas III have evaluated the performance of these TALE based proteins against the usual DNA sequences, and by substituting the first DNA letter from T to remaining three nucleosides to find that a majority of natural as well as artificial designer TALE proteins follow the “T-exception” and lose most of their activity when the initial nucleoside base is changed from thymidine. Once this was established, they started searching for ways to design new TALE proteins which can overcome this barrier. They adopted Andrew C. Mercer’s directed evolution technique by generating a large library of novel TALE proteins with random varying structures assumed to be responsible for attaching itself to initial nucleoside. These new TALE proteins are subjected to further tests, where they found that many TALE proteins could effectively bind with non-T nucleosides as well. This breakthrough has dramatically increased the number of DNA sites that can be targeted effectively with great precision, hence uncovering the potential uses of this method in a wide range of applications.
Further information about this study can be easily accessed here on Nucleic Acids Research.
Source: The Scripps Research Institute