Single-molecule DNA visualization using AT-specific red and non-specific green DNA-binding fluorescent proteins

Analyst. 2019 Jan 28;144(3):921-927. doi: 10.1039/c8an01426d.

Abstract

The recent advances in the single cell genome analysis are generating a considerable amount of novel insights into complex biological systems. However, there are still technical challenges because each cell has a single copy of DNA to be amplified in most single cell genome analytical methods. In this paper, we present a novel approach to directly visualize a genomic map on a large DNA molecule instantly stained with red and green DNA-binding fluorescent proteins without DNA amplification. For this visualization, we constructed a few types of fluorescent protein-fused DNA-binding proteins: H-NS (histone-like nucleoid-structuring protein), DNA-binding domain of BRCA1 (breast cancer 1), high mobility group-1 (HMG), and lysine tryptophan (KW) repeat motif. Because H-NS and HMG preferentially bind A/T-rich regions, we combined A/T specific binder (H-NS-mCherry and HMG-mCherry as red color) and a non-specific complementary DNA binder (BRCA1-eGFP and 2(KW)2-eGFP repeat as green color) to produce a sequence-specific two-color DNA physical map for efficient optical identification of single DNA molecules.

MeSH terms

  • DNA / analysis*
  • DNA / chemistry
  • DNA / metabolism
  • DNA-Binding Proteins / metabolism*
  • Green Fluorescent Proteins / metabolism*
  • Humans
  • Image Processing, Computer-Assisted / methods*
  • Microscopy, Fluorescence / methods*
  • Single-Cell Analysis / methods*

Substances

  • DNA-Binding Proteins
  • Green Fluorescent Proteins
  • DNA