Comparative analysis of new, mScarlet-based red fluorescent tags in Caenorhabditis elegans

• Published in: Genetics (Austin) Vol. 228; no. 2
• Main Authors: Cao, Wen Xi, Merritt, Daniel M, Pe, Karinna, Cesar, Michael, Hobert, Oliver
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 07.10.2024
• Subjects: Brief Investigation; C. elegans; Fluorophore; RFP; marker
• ISSN: 1943-2631; 0016-6731; 1943-2631
• DOI: 10.1093/genetics/iyae126

One problem that has hampered the use of red fluorescent proteins in the fast-developing nematode C. elegans has been the substantial time delay in maturation of several generations of red fluorophores. The recently described mScarlet-I3 protein has properties that may overcome this limitation. We compare here the brightness and onset of expression of CRISPR/Cas9 genome-engineered mScarlet, mScarlet3, mScarlet-I3 and GFP reporter knock-ins. Comparing the onset and brightness of expression of reporter alleles of C. elegans golg-4, encoding a broadly expressed Golgi resident protein, we found that the onset of detection of mScarlet-I3 in the embryo is several hours earlier than older versions of mScarlet and comparable to GFP. These findings were further supported by comparing mScarlet-I3 and GFP reporter alleles for pks-1, a gene expressed in the CAN neuron and cells of the alimentary system, as well as reporter alleles for the panneuronal, nuclear marker unc-75. Hence, the relative properties of mScarlet-I3 and GFP do not depend on cellular or subcellular context. In all cases, mScarlet-I3 reporters also show improved signal-to-noise ratio compared to GFP.