Open AccessMetabolic Behaviour of Nonhistone Chromosomal Proteins in Proliferating and in Resting Fibroblasts
Author(s) -
DJONDJUROV Lalju Petrov,
IVANOVA Emilia Christova,
TSANEV Roumen Georgiev
Publication year - 1977
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1977.tb11697.x
Subject(s) - trypsinization , non histone protein , biology , biochemistry , chinese hamster , thymidine , cell , dna , wi 38 , metabolism , cell division , ploidy , chromatin , mitosis , cell culture , microbiology and biotechnology , trypsin , genetics , gene , enzyme
The metabolism of nonhistone chromosomal proteins was studied in two lines of cells showing a different degree of contact inhibition: human diploid fibroblasts, which are easily contact‐inhibited, and Chinese hamster fibroblasts, which had been made to stop proliferating by fasting. By following the 3 H/ 14 C ratio of [ 3 H]tryptophan‐labelled nonhistone chromosomal proteins and [ 14 C]thymidine‐labelled DNA in chase experiments three main groups of these proteins could be detected with respect to their metabolic behaviour: (a) a metabolically stable group which is acid‐insoluble and represents the bulk of nonhistone chromosomal proteins in proliferating cells; this group is conserved when the cells enter a resting phase; (b) a metabolically labile group which is acid‐insoluble and is observed as a minor fraction in proliferating cells; (c) a metabolically labile group which is acid‐insoluble and accumulates in resting cells; this fraction is much larger in contact‐inhibited cells. Stimulation of cell proliferation by trypsinization decreases the amount of nonhistone chromosomal proteins in resting cells to the basic level observed in proliferating cells.