Cell context-dependent CFI-1/ARID3 functions control neuronal terminal differentiation

CFI-1/ARID3 functions unilaterally to restrict gap junction formation inC. elegans

“…In C. elegans , cfi-1 was originally cloned based upon its role in the development of neuronal diversity (Shaham and Bargmann, 2002). Through the generation of an in vivo binding map on the C. elegans genome, Li et al recently identified that the majority of CFI-1 targeting genes encode markers associated with neuronal terminal differentiation (Li et al, 2023). Therefore, CFI-1 may act a terminal selector, orchestrating the terminal differentiation of distinct neuron types.…”

“…Within the PVCs, CFI-1 may directly modulate the gene expression of gap junction proteins, thereby exerting control over the quantity or abundance of gap junction connections. The whole genome binding map did not identify innexin unc-9 as a direct target gene of CFI-1 (Li et al, 2023). However, given the limited number of neurons (confined to PVC and PVR) in which gap junction formation is influenced by cfi-1 , it is difficult to rule out the possibility that cfi-1 could directly regulate the gene expression of UNC-9 or other gap junction proteins.…”

Efficacy of auxin-inducible protein degradation inC. eleganstissues using different auxins and TIR1-expressing strains

“…We observed that auxin-mediated CFI-1 depletion was accompanied by an increase in the number of motor neurons expressing glr-4 . Hence, CFI-1 is required in the adult stage to repress glr-4 in nerve cord motor neurons 7 . This protocol can be combined with any C. elegans behavioral assays (e.g., harsh/gentle touch, osmotic avoidance, locomotion with automated worm tracking). Essentially, instead of preparing a microscope slide to evaluate gene expression, behavioral assays can be conducted, like for example the harsh touch used in the original study 7 .…”

“…For temporally-controlled depletion of mNG::AID::3xFLAG::CFI-1, in our original study 7 , we placed L4 animals on NGM-auxin (4mM) and control plates for 2 days and examined expression of the cholinergic motor neuron-specific reporter glr-4 (mScarlet) with fluorescence microscopy at the adult (Day 2) adult stage. We observed that auxin-mediated CFI-1 depletion was accompanied by an increase in the number of motor neurons expressing glr-4 .…”

“…Here, we present a detailed protocol to perform AID-driven spatiotemporal depletion of specific proteins in C. elegans tissues. First, we introduced the AID degron and a fluorescent reporter at two conserved proteins: (a) the transcription factor CFI-1 (human ARID3), which is expressed in the nucleus of multiple C. elegans neurons and head muscle cells 6,7 , and (b) the broadly expressed translation initiation factor Y47D3A.21 (human DENR) that localizes in the cytoplasm. Second, we provide a step-by-step guide on how to generate C. elegans strains suitable for AID-mediated protein (CFI-1 and DENR) depletion.…”