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Arrest of cell cycle progression of HeLa cells in the early G1 phase in K + ‐depleted conditions and its recovery upon addition of insulin and LDL
Author(s) -
Yamaguchi Hisao,
Hosokawa Keiko,
Jiang ZhengLin,
Takahashi Akira,
Ikehara Toshitaka,
Miyamoto Hiroshi
Publication year - 1993
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240530103
Subject(s) - hela , cell cycle progression , cell cycle , microbiology and biotechnology , insulin , cell , chemistry , biology , biochemistry , endocrinology
Cell cycle progression of synchronized HeLa cells was studied by measuring labeling of the nuclei with [ 3 H]thymidine. The progression was arrested in a chemically defined medium in which K + was replaced by Rb + (Rb‐CDM) but was restored upon addition of insulin and/or low density lipoprotein (LDL). Cells started DNA synthesis 12 hr after addition of insulin and/or LDL, regardless of the time of arrest, suggesting their arrest early in the G1 phase. After incubation of cells in Rb‐CDM containing insulin or LDL singly for 3, 6, or 9 hr, replacement of the medium by that without an addition resulted in marked delay in entry of cells into the S phase, but in its replacement by medium containing both agents, the delay was insignificant. Synthesis of bulk protein, estimated as increase in the cell volume, was not strongly inhibited. From these results we conclude that cell cycle progression of HeLa cells in K − ‐depleted CDM is arrested early in the G1 phase and that the arrest is due to lack of some protein(s) required for entry into the S phase that is synthesized in the early G1 phase.