title: Jedi--a novel transmembrane protein expressed in early hematopoietic cells.
abstract: Self-renewal and differentiation of hematopoietic stem and progenitor cells are defined by the ensembles of genes expressed by these cells. Here we report identification of a novel gene named Jedi, which is expressed predominantly in short- and long-term repopulating stem cells when compared to more mature bone marrow progenitors. Jedi mRNA encodes a transmembrane protein that contains multiple EGF-like repeats. Jedi and two earlier reported proteins, MEGF10 and MEGF11, share a substantial homology and are likely to represent a novel protein family. Studies of the potential role of Jedi in hematopoietic regulation demonstrated that the retrovirally mediated expression of Jedi in bone marrow cells decreased the number of myeloid progenitors in in vitro clonogenic assays. In addition, expression of Jedi in NIH 3T3 fibroblasts resulted in a decreased number of late and early myeloid progenitors in the non-adherent co-cultured bone marrow cells. Jedi shares a number of structural features with the Jagged/Serrate/Delta family of Notch ligands, and our experiments indicate that the extracellular domain of Jedi, similar to the corresponding domain of Jagged1, inhibits Notch signaling. On the basis of obtained results, we suggest that Jedi is involved in the fine regulation of the early stages of hematopoietic differentiation, presumably through the Notch signaling pathway.
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, 310 East 67 Street, New York, NY 10021, USA.
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Krivtsov
authors.forename: Fedor N
authors.initials: FN
authors.lastname: Rozov
authors.forename: Marina V
authors.initials: MV
authors.lastname: Zinovyeva
authors.forename: P Jan
authors.initials: PJ
authors.lastname: Hendrikx
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Jan W M
authors.initials: JW
authors.lastname: Visser
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Belyavsky
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D001854:Bone Marrow Cells / Q000821:virology; D002454:Cell Differentiation; D002460:Cell Line; D045744:Cell Line, Tumor; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D011817:Rabbits; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D012190:Retroviridae / Q000235:genetics / Q000254:growth & development; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D014162:Transfection
chemical_list: C522125:Jedi protein, mouse; D008565:Membrane Proteins; D051880:Receptors, Notch; D004815:Epidermal Growth Factor