title: Stage-specific expression of Clast6/E3/LAPTM5 during B cell differentiation: elevated expression in human B lymphomas.
abstract: We have identified a CD40-regulated gene, Clast6/E3/LAPTM5, by subtraction of cDNAs derived from resting and CD40 ligand-treated B cells. Clast6/E3/LAPTM5 is abundantly expressed in resting mature B cells but is rapidly and transiently repressed by treatment with CD40 ligand, a T helper signal that induces B cell activation. Using a fluorescence activated cell sorter, we have purified B-lineage cells into distinct populations based on their differential expression of cell surface markers. Clast6/E3/LAPTM5 was found to be highly expressed in progenitor and precursor B cells, downregulated in late pre-B and immature B cells, and upregulated again in mature B and the germinal center B cells. Interestingly, Clast6/E3/LAPTM5 was expressed at high levels in malignant B lymphomas. These results reveal stage-specific expression of Clast6/E3/LAPTM5 during B cell differentiation and implicates its possible involvement in B cell malignancies.
authors.affiliation: Division of Pathology, Chiba Cancer Center Research Institute, Chiba 260-8717, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Seimiya
authors.forename: Jiyang
authors.initials: J
authors.lastname: O-Wang
authors.forename: Rumana
authors.initials: R
authors.lastname: Bahar
authors.forename: Kiyoko
authors.initials: K
authors.lastname: Kawamura
authors.forename: Yanqing
authors.initials: Y
authors.lastname: Wang
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Saisho
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Tagawa
mesh_terms: D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D002454:Cell Differentiation; D002471:Cell Transformation, Neoplastic; D003593:Cytoplasm / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D015972:Gene Expression Regulation, Neoplastic; D018858:Germinal Center / Q000166:cytology; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology / Q000378:metabolism; D016393:Lymphoma, B-Cell / Q000209:etiology / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D013382:Subtraction Technique
chemical_list: D008565:Membrane Proteins; C100848:LAPTM5 protein, human