title: Expression, purification, and characterization of a novel soluble form of human Delta-like-1.
abstract: The notch signaling pathway plays an important role in inhibiting cell differentiation and enhancing the repopulation capability of hematopoietic stem/progenitor cells. In this study, we developed rhDSL, a novel soluble form of Notch ligand Delta-like-1, which contains the DSL domain and the N-terminal sequence of the ligand, and investigated its function in ex vivo expansion of human umbilical cord blood (UCB)-primitive hematopoietic cells. The coding sequence for rhDSL was cloned into a pQE30 vector, and the recombinant rhDSL, fused with a 6x His tag, was expressed in Escherichia coli as inclusion bodies after isopropyl beta-D-thiogalactoside induction. After renaturing by dilutions, the protein was purified through anion exchange followed by affinity chromatography. The purity of rhDSL protein was more than 99% with very low endotoxin. In combination with human c-kit ligand, the effect of rhDSL on ex vivo expansion of UCB CD34(+) cells was found to be optimal at 1.5 microg/ml of rhDSL. The rhDSL protein might therefore be a potential supplement for the expansion of UCB-primitive hematopoietic cells.
authors.affiliation: Laboratory of Regenerative Medicine, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zhao
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Wu
authors.forename: Lingchen
authors.initials: L
authors.lastname: Guo
authors.forename: Junfen
authors.initials: J
authors.lastname: Jiang
authors.forename: Weiwei
authors.initials: W
authors.lastname: Huang
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Lin
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Xiang
authors.forename: Huili
authors.initials: H
authors.lastname: Lu
authors.forename: Shunying
authors.initials: S
authors.lastname: Zhu
authors.forename: Yan
authors.initials: Y
authors.lastname: Yu
authors.forename: Anja
authors.initials: A
authors.lastname: Moldenhauer
authors.forename: Wei
authors.initials: W
authors.lastname: Han