hMSH2-hMSH6 Interaction with Mismatched DNA
Sarah Javaid
Human MutS homolog (MSH) heterodimeric protein hMSH2-hMSH6 plays a critical role in maintaining genetic stability by correcting mismatched nucleotides via the repair of the DNA replication errors. Mutations in hMSH2-hMSH6 result in elevated spontaneous mutation rate and susceptibility to a common cancer predisposition syndrome, Hereditary Non-Polyposis Colorectal Cancer (HNPCC). The detailed conformational transitions of hMSH2-hMSH6 and the role of adenosine nucleotides and mismatched DNA are currently unknown.
We will develop a fluorescence resonance energy transfer (FRET) real-time methodology which will examine conformational transitions. The FRET methodology will be used to examine conformational transitions associated with hMSH2-hMSH6. The transitions of hMSH2-hMSH6 will be examined in the presence i) mismatch and homoduplex oligonucleotide and ii) adenosine nucleotides.
Proton NMR and MRI study of sub-millimeter sized biological
objects
Seongjin Choi
NMR microscopy has been conducted since the onset of MRI of biological applications and significant advances have been made recently. MR microscopy has been used for studying seeds complementary to traditional methods and recent studies have largely focused on the monitoring of water uptake and oil distribution during imbibition, which is a crucial process in seed germination. Although many NMR and MRI studies have been conducted on various seeds, very "small (<1mm) dry seeds" have not been studied extensively except one study. In our study, the fundamental measurements (NMR spectra, T1 and T2) of small dry seeds of four different plant species were conducted by MR imaging and spectroscopy using NMR microscopy system which is capable of investigating miniature objects (up to 750μm in diameter and 2mm in length). In addition, the spectroscopic and anatomical changes of a single Nicotiana tabacum (tobacco) seed embedded in wet sand were monitored during an extended imbibition to evaluate the role of MRI to study germination and as a complementary method to the conventional conductivity test.