6yov
OCT4-SOX2-bound nucleosome - SHL+6
Structural highlights
Disease[SOX2_HUMAN] Defects in SOX2 are the cause of microphthalmia syndromic type 3 (MCOPS3) [MIM:206900]. Microphthalmia is a clinically heterogeneous disorder of eye formation, ranging from small size of a single eye to complete bilateral absence of ocular tissues (anophthalmia). In many cases, microphthalmia/anophthalmia occurs in association with syndromes that include non-ocular abnormalities. MCOPS3 is characterized by the rare association of malformations including uni- or bilateral anophthalmia or microphthalmia, and esophageal atresia with trachoesophageal fistula.[1] Function[SOX2_HUMAN] Transcription factor that forms a trimeric complex with OCT4 on DNA and controls the expression of a number of genes involved in embryonic development such as YES1, FGF4, UTF1 and ZFP206 (By similarity). Critical for early embryogenesis and for embryonic stem cell pluripotency. May function as a switch in neuronal development. Downstream SRRT target that mediates the promotion of neural stem cell self-renewal (By similarity). Keeps neural cells undifferentiated by counteracting the activity of proneural proteins and suppresses neuronal differentiation (By similarity).[2] [GFP_AEQVI] Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin. [H2B1J_HUMAN] Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling.[3] [4] [5] Has broad antibacterial activity. May contribute to the formation of the functional antimicrobial barrier of the colonic epithelium, and to the bactericidal activity of amniotic fluid.[6] [7] [8] Publication Abstract from PubMedTranscription factors (TFs) regulate gene expression through chromatin where nucleosomes restrict DNA access. To study how TFs bind nucleosome-occupied motifs we focused on the reprogramming factors OCT4 and SOX2. We determined TF engagement throughout a nucleosome at base-pair resolution in vitro, enabling cryo-EM structure determination at two preferred positions. Depending on motif location, OCT4-SOX2 differentially distort nucleosomal DNA. At one position, OCT4-SOX2 removes DNA from Histone H2A/Histone H3 (H2A/H3); however, at an inverted motif, the TFs only induce local DNA distortions. OCT4 uses one of its two DNA binding domains to engage DNA in both structures, reading-out a partial motif. These findings explain site specific nucleosome engagement by the pluripotency factors OCT4-SOX2 and reveal how TFs distort nucleosomes to access chromatinized motifs. Mechanisms of OCT4-SOX2 motif readout on nucleosomes.,Michael AK, Grand RS, Isbel L, Cavadini S, Kozicka Z, Kempf G, Bunker RD, Schenk AD, Graff-Meyer A, Pathare GR, Weiss J, Matsumoto S, Burger L, Schubeler D, Thoma NH Science. 2020 Apr 23. pii: science.abb0074. doi: 10.1126/science.abb0074. PMID:32327602[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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