title: Two color RNA intercalating probe for cell imaging applications.
abstract: Here we report on a phenanthridine derivative which has a covalently linked fluorescein molecule in order to increase the light absorption and hence fluorescence signal intensity when bound to duplex RNA. Steady-state fluorescence shows that the energy transfer efficiency from the fluorescein to the phenanthridine fluorophore is approximately 77%, which results in the probe being over 5x brighter than other phenanthridine derivatives when bound to RNA. Due to the relatively long lifetime (approximately 20 ns) of the probe, time-resolved fluorescence is used to increase the signal to background ratio in cell growth medium from 7 (steady-state value) to over 40. Moreover, fluorescence images of cells containing the probe show that the fluorescein signal is readily apparent along with that of the intercalated fluorophore, allowing this probe to be used as a dual color probe which simultaneously reports the probes' location and that of RNA.
authors.affiliation: Departments of Chemistry and Chemical Engineering, Columbia University, New York, New York 10027, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Stevens
authors.forename: Naphtali
authors.initials: N
authors.lastname: O'Connor
authors.forename: Harshad
authors.initials: H
authors.lastname: Vishwasrao
authors.forename: Diana
authors.initials: D
authors.lastname: Samaroo
authors.forename: Eric R
authors.initials: ER
authors.lastname: Kandel
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Akins
authors.forename: Charles M
authors.initials: CM
authors.lastname: Drain
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Turro
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000737:chemistry / Q000378:metabolism; D005452:Fluoresceins / Q000737:chemistry* / Q000493:pharmacokinetics; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D005456:Fluorescent Dyes / Q000737:chemistry* / Q000493:pharmacokinetics; D006801:Humans; D007364:Intercalating Agents / Q000737:chemistry* / Q000493:pharmacokinetics; D008325:Mammary Neoplasms, Experimental / Q000737:chemistry / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D010617:Phenanthridines / Q000737:chemistry* / Q000493:pharmacokinetics; D012313:RNA / Q000032:analysis* / Q000737:chemistry; D012331:RNA, Fungal / Q000032:analysis; D013050:Spectrometry, Fluorescence / Q000379:methods; D015003:Yeasts / Q000737:chemistry / Q000235:genetics
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D007364:Intercalating Agents; D010617:Phenanthridines; D012331:RNA, Fungal; D012313:RNA