Figure 1: Schematic of how the genetically-encoded photosensitizer miniSOG is used for Chromophore-Assisted Light-Inactivation (CALI) of mitochondrial respiratory chain complex II.

The C. elegans gene mev-1 codes for one of four nuclear encoded subunits that comprise mitochondrial complex II, also known as mitochondrial succinate:ubiquinone oxidoreductase (in mammals, this complex is comprised of SDH subunits (A–D). The native mev-1 gene (mev-1(+)) resides on chromosome III as indicated by the arrow. Two mutant alleles were used in this study, mev-1(kn1)III and mev-1(tm1081)III. The kn1 allele contains a G71E point mutation resulting in a strain with a decreased brood size and sensitivity to paraquat¹¹. The tm1081 allele is a deletion that results in a lethal/sterile phenotype. The genetically-encoded photosensitizer miniSOG was inserted into a mev-1 genomic fragment so as to create a fusion tag at the C-terminus, and the synthetic mev-1::minSOG transgene was integrated on chromosome II (arrow) using Mos1-mediated single-copy insertion (MosSCI). Either an active (able to produce ROS in response to light) or inactive (not able to produce ROS) variant of miniSOG was used to account for tagging and expression artifacts. Alleles are abbreviated as follows, mev-1(+)III as “+”, mev-1(kn1)III as “kn1”, mev-1(tm1081)III as “tm1081”, rnySi29 as “inactive”, and rnySi19 as “active”.