Table 3.

A comparison of in-cell spFRET with other techniques for the in vivo structural characterization of DNA

	In-cell NMR	In-cell PELDOR	In-cell spFRET
Disturbance of native environment	Yes	Yes	No
Cell type	X. laevis egg/oocyte	X. laevis egg/oocyte	E. coli, mammalian cellsa
Toxicity	Sequence dependentb	Sequence dependentb	No
Subcellular localization	Nucleus/cytosolc	Nucleus/cytosolc	Nucleusd
Tag requirement	No	Yes	Yes
Measurement time span	Hours	< 70 mine	Hours
Structural informationf	Short-range	Long-range	Long-range

^aIllustrated here for human epitheloid carcinoma (HeLa) cells (Supplementary Figure S9).

^bSee the text for details.

^cFor both in-cell NMR and PELDOR, the issue of the intracelllular localization of introduced DNA has not been properly addressed in the literature. In X. laevis, localization experiments using fluorescently-labeled DNA mini-haiprin suggest that ∼90% of introduced DNA is localized in the nucleus and ∼10% in the cytosol (41).

^dApplies for mammalian cells (37–40).

^eRef (3,4,42).

^fShort-range—typically < 5 Å; long range—typically < 50 Å.