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Embryonic stem (ES) cells are pluripotent-undifferentiated cells that have a great interest for the investigation of developmental biology. Murine ES cells maintain their pluripotency by the supplementation of the leukemia inhibitory factor (LIF). LIF is reported to act as a matrix-anchored form, and immobilized cytokines are useful to sustain their signaling on target cells. In this study, we used the immobilizable fusion protein composed of LIF and IgG-Fc region, which was used as a model of the matrix-anchored form of LIF to establish a novel system for ES cell culture and to investigate the effect of immobilized LIF on maintenance of ES cell pluripotency. Mouse ES cells maintained their undifferentiated state on the surface coated with LIF-Fc. Furthermore, when cultured on the co-immobilized surface with LIF-Fc and E-cadherin-Fc, mouse ES cells showed characteristic scattering morphologies without colony formation, and they could maintain their undifferentiated state and pluripotency without additional LIF supplementation. The activation of LIF signaling was sustained on the co-immobilized surface. These results indicate that immobilized LIF and E-cadherin can maintain mouse ES cells efficiently and that the immobilizable LIF-Fc fusion protein is useful for the investigation of signaling pathways of an immobilized form of LIF in the maintenance of ES cell pluripotency.

Olefins with a phenathroline ring and a pyrrole ring were prepared and hydrogen atom transfer reaction in the excited singlet state was observed. The tautomer produced in the excited singlet state has lifetime of 30–50 ps for cis-1 and c,t-2 and with fluorescence maximum at longer wavelength region at 640 nm. The compound 1 exhibited photochromic behavior with its absorption maximum changing between 380 nm and 440 nm, while 2 exhibited only the small change of the absorption spectra on photoirradiation. Copyright © 2007 John Wiley & Sons, Ltd.

1. The role of synaptophysin in the exocytotic release of dopamine (DA) was examined in Xenopus laevis oocytes injected with rat brain mRNA.