title: Specificity protein 1 regulates topoisomerase IIβ expression in SH-SY5Y cells during neuronal differentiation.
abstract: Topoisomerase IIβ (top IIβ) is a nuclear enzyme with an essential role in neural development. The regulation of top IIβ gene expression during neural differentiation is poorly understood. Functional analysis of top IIβ gene structure displayed a GC box sequence in its transcription promoter, which binds the nuclear transcription factor specificity protein 1 (Sp1). Sp1 regulates gene expression via multiple mechanisms and is essential for early embryonic development. This study seeks to determine whether Sp1 regulates top IIβ gene expression during neuronal differentiation. For this purpose, human neuroblastoma SH-SY5Y cells were induced to neuronal differentiation in the presence of all-trans retinoic acid (RA) for 5 days. After incubation with 10 μM RA for 3-5 days, a majority of the cells exited the cell cycle to become postmitotic neurons, characterized by the presence of longer neurite outgrowths and expression of the neuronal marker microtubule-associated protein-2 (MAP2). Elevated Sp1 and top IIβ mRNA and protein levels were detected and found to be positively correlated with the differentiation stage. Chromatin immunoprecipitation assay demonstrated an increased recruitment of Sp1 to the top IIβ promoter after RA treatment. Mithramycin A, a compound that interferes with Sp1 binding to GC-rich DNA sequences, downregulated the expression of top IIβ, resulting in reduced expression of MAP2 and decreased neurite length compared with the control group. Our results indicate that Sp1 regulates top IIβ expression by binding to the GC box of the gene promoter during neuronal differentiation in SH-SY5Y cells.
authors.affiliation: Cell Biology Division, Institute of Basic Medicine, Hebei Medical University, Shijiazhuang, Hebei, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Guo
authors.forename: Cuili
authors.initials: C
authors.lastname: Cao
authors.forename: Xueqian
authors.initials: X
authors.lastname: Chi
authors.forename: Junxia
authors.initials: J
authors.lastname: Zhao
authors.forename: Xia
authors.initials: X
authors.lastname: Liu
authors.forename: Najing
authors.initials: N
authors.lastname: Zhou
authors.forename: Shuo
authors.initials: S
authors.lastname: Han
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Yan
authors.forename: Yanling
authors.initials: Y
authors.lastname: Wang
authors.forename: Yannan
authors.initials: Y
authors.lastname: Xu
authors.forename: Yunli
authors.initials: Y
authors.lastname: Yan
authors.forename: Huixian
authors.initials: H
authors.lastname: Cui
authors.forename: Hongxia
authors.initials: H
authors.lastname: Sun
mesh_terms: D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D047369:Chromatin Immunoprecipitation; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007641:Keratolytic Agents / Q000494:pharmacology; D016501:Neurites / Q000187:drug effects / Q000502:physiology; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D016329:Sp1 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D004268:DNA-Binding Proteins; D007641:Keratolytic Agents; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D014212:Tretinoin; D004250:DNA Topoisomerases, Type II
keywords: gene expression; neurite outgrowth; neuronal differentiation; transcription factors