Constitutes a precursor of the transcription factor (PubMed:28441531). Mediates the autocatalytic cleavage that releases the Myelin regulatory factor homolog 1, N-terminal component that specifically activates transcription of genes involved in synaptic rewiring during nervous system maturation (PubMed:28441531). Membrane-bound part that has no transcription factor activity and remains attached to the endoplasmic reticulum membrane following cleavage. Transcription factor that specifically activates expression of genes involved in synaptic rewiring during nervous system maturation (PubMed:28441531). Specifically required for dorsal D (DD) GABAergic motor neurons synaptic rewiring (PubMed:28441531, PubMed:33950834). Acts in complex with myrf-2 paralog (PubMed:28441531). Homotrimer (By similarity). Interacts with myrf-2 (PubMed:28441531). Interacts (via C-terminus) with pan-1 (via LRR regions); the interaction promotes the role of myrf-1 in the synaptic remodeling of DD GABAergic motor neurons at the cell membrane (PubMed:33950834). In early L1 larvae, localizes to the cell membrane of the pharynx, epidermis, and neurons, but is not enriched in the nucleus or cytoplasm of these cell types (PubMed:33950834). Later in the L1 larval stage, accumulates in the nucleus of the pharynx, epidermis, and neurons (PubMed:33950834). Translocates from the cytoplasm to the nucleus upon autocatalytic cleavage (PubMed:28441531). In early L1 larvae, localizes to the cell membrane of the pharynx, epidermis, and neurons, but is not enriched in the nucleus or cytoplasm of these cell types (PubMed:33950834). Cell membrane localization is promoted by pan-1 (PubMed:33950834). Later in the L1 larval stage, accumulates in the nucleus of the pharynx, epidermis, and neurons (PubMed:33950834). Widely expressed in many tissues, including neuronal, muscle and epidermal stem cells (PubMed:21989027). In neurons, expressed in dorsal D (DD) GABAergic motor neurons (PubMed:28441531). In early L1 larvae, expressed in the pharynx, epidermis, and neurons. In early L1 larvae, expressed in the pharynx, epidermis, and neurons. Myelin regulatory factor: The peptidase S74 domain, also named Intramolecular Chaperone Auto-processed (ICA) domain or Intramolecular Chaperone Domain (ICD), has protease activity and mediates autocatalytic processing of the protein to generate the Myelin regulatory factor, N-terminal active transcription factor and the Myelin regulatory factor, C-terminal components. Myelin regulatory factor: Follows autocatalytic cleavage via the peptidase S74 domain. Autoprocessing is apparently constitutive and is essential for transcriptional activity. Worms show normal dorsal D (DD) GABAergic motor neurons rewiring but show larval lethality. Worms lacking both myrf-1 and myrf-2 display defective DD neurons rewiring. Belongs to the MRF family.