Studies of DNA Methyltransferases

描述（由申请人提供）：该项目利用了Pacific Biosciences新开发的称为SMRT测序的DNA测序技术。除了提供DNA碱基序列之外，该方法还允许检测修饰的碱基。DNA甲基转移酶传统上是相当困难的表征，因此，我们目前不知道任何DNA甲基转移酶的准确的DNA识别特异性。对于构成限制-修改制度一部分的那些， 通常认为它们具有与限制性内切酶相同的识别特异性。然而，在某些系统中，初步结果表明，这可能不是这样的，我们现在可以明确地测试这一点。对特异性的了解将是许多方面的关键。首先，在某些情况下，它将使这些甲基转移酶成为有价值的商业试剂。其次，我们希望发现新的DNA甲基转移酶的性质，使他们适合于特定的应用。最近发现的一种这样的酶是M.EcoGI，它似乎识别序列中的所有A残基，并以非常高的效率将它们转化为N6-甲基腺嘌呤。这个项目的结果也将大大提高我们在新英格兰生物实验室克隆的限制修饰系统的价值，也将大大有助于新确定的DNA序列的功能注释。它是学术和商业研究的理想结合，因此特别适合新英格兰生物实验室。

DESCRIPTION (provided by applicant): This project takes advantage of a DNA sequencing technology newly developed by Pacific Biosciences called SMRT sequencing. In addition to providing the DNA base sequence, this approach also allows the detection of modified bases. DNA methyltransferases have traditionally been rather difficult to characterize and as a result, we do not currently know the accurate DNA recognition specificity of any DNA methyltransferases. In the case of those that form part of restriction-modification systems, it has always been assumed that they will have the same recognition specificity as the restriction enzyme. However, in some systems preliminary results indicated that this might not be so, and we now in a position to test that explicitly. A knowledge of the specificity will be key on many fronts. Firstly, in some cases it will allow these methyltransferases to become valuable commercial reagents. Secondly, we expect to discover novel DNA methyltransferases with properties that would make them suitable for specific applications. One such enzyme discovered very recently, is M.EcoGI, which appears to recognize all A residues in a sequence and convert them at very high efficiency to N6- methyladenine. The results of this project will also greatly enhance the value of the cloned restriction-modification systems that we have at New England Biolabs and will also help considerably in the functional annotation of newly determined DNA sequences. It is an ideal blend of academic and commercial research and therefore is especially suited for New England Biolabs.