title: CD99 type II is a determining factor for the differentiation of primitive neuroectodermal cells.
abstract: CD99 is a 32-kDa cell surface molecule present on thymocytes, peripheral T cells, many other hematopoietic stem cells and somatic cells were implicated in cell-cell adhesion and cell-activation phenomena. Two major subtypes have been identified so far, designated CD99 type I and type II. We have investigated the correlation between the degree of neural differentiation and the expression of CD99 subtypes in three differentially differentiated cell lines such as CADO-ES1, RD-ES, and SH-N-SY5Y, in order of differentiation. In addition, we induced differentiation of the RD-ES cell line by N6,2'-dibutyryl-cAMP (db-cAMP). Six days after treatment with db-cAMP, RD-ES cell line has changed its morphology from uniform round cells to cells with neurites, and initially CD99 type II-overexpressed RD-ES cells showed significant down-regulation of CD99 type II, whereas CD99 type I expression remained constant. When RD- ES cells were transfected with the cDNA encoding for CD99 type I-green fluorescence protein (GFP) and type II-GFP, CD99 type II transfected RD-ES cell line remained unchanged with morphology of undifferentiated form. Our data suggest that CD99 type II acts as a negative regulator in the neural differentiation of precursor cells that might occur during nerve system development.
authors.affiliation: Department of Pathology, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Hyun Gyu
authors.initials: HG
authors.lastname: Lee
authors.forename: Sung Hye
authors.initials: SH
authors.lastname: Park
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Choi
authors.forename: Seong Hoe
authors.initials: SH
authors.lastname: Park
mesh_terms: D000071443:12E7 Antigen; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D048429:Cell Size / Q000187:drug effects; D004475:Ectoderm / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D016501:Neurites / Q000187:drug effects; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D020033:Protein Isoforms; D003994:Bucladesine