Constitutes a precursor of the transcription factor. Mediates the autocatalytic cleavage that releases the Myelin regulatory factor, N-terminal component that specifically activates transcription of central nervous system (CNS) myelin genes. 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 myelin genes such as MBP, MOG, MAG, DUSP15 and PLP1 during oligodendrocyte (OL) maturation, thereby playing a central role in oligodendrocyte maturation and CNS myelination (PubMed:19596243, PubMed:22956843, PubMed:23966833, PubMed:24204311, PubMed:27532821). Specifically recognizes and binds DNA sequence 5'-CTGGYAC-3' in the regulatory regions of myelin-specific genes and directly activates their expression. Not only required during oligodendrocyte differentiation but is also required on an ongoing basis for the maintenance of expression of myelin genes and for the maintenance of a mature, viable oligodendrocyte phenotype (PubMed:19596243, PubMed:22956843, PubMed:23966833). Homotrimer (PubMed:23966833, PubMed:28623291). Interacts (via C-terminal region) with TMEM98; the interaction inhibits MYRF self-cleavage (PubMed:30249802). Translocates from the cytoplasm to the nucleus upon autocatalytic cleavage. Specifically expressed by postmitotic oligodendrocytes in the CNS. Not detected in the peripheral nervous system (PNS). At postnatal day 3 (P3), the expression is restricted to cells in the hindbrain and cerebellum, subsequently spreading rostrally throughout the white matter tracks over the first 2 weeks postnatal, mirroring the expression of Plp1. Expression is directly regulated by SOX10. The nuclear localization signals mediate translocation to the nucleus. 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. Glycosylated. Follows autocatalytic cleavage via the peptidase S74 domain. Autoprocessing is apparently constitutive and is essential for transcriptional activity (PubMed:23966833, PubMed:28623291, PubMed:30249802). Autocatalytic cleavage is inhibited by interaction with TMEM98 (PubMed:30249802). Embryos die around 12.5 dpc. Conditional knockout mice in which Mrf is lacking within the oligodendrocyte lineage display severe deficits in myelin gene expression and premyelinating oligodendrocytes fail to myelinate. These mice display severe neurological abnormalities and die because of seizures during the third postnatal week. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Dubious isoform due to intron retention. Belongs to the MRF family.