Epigenetic variation of cultured somatic cells: evidence for gradual changes in the requirement for factors promoting cell division.
Cells of higher plant species in culture sometimes lose their requirement for an exogenous supply of a cell division factor that, thereafter, they are able to produce. This heritable change, known as cytokinin habituation, appears to be an epigenetic one rather than a classical mutation because it is directed, potentially reversible, leaves the cell totipotent, and involves the expression of a latent differentiated function. By using cloned cell lines derived from pith parenchyma of tobacco, we have obtained evidence that the habituation process is gradual rather than all-or-none and leads to progressively more autotrophic tissues. Cells in culture show reversible shifts among a range of habituated states but remain totipotent and can be induced to regain their requirement for a cell division factor. Thus, it appears that habituation involves epigenetic changes in a quantitative cellular phenotype. Our findings support the hypothesis that tumor progression in crown gall, a neoplastic disease of higher plants, can be accounted for by heritable changes in the pattern of gene expression.
D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D002999:Clone Cells / Q000166:cytology; D003583:Cytokinins / Q000494:pharmacology*; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology*; D010947:Plants, Toxic; D013997:Time Factors; D014026:Nicotiana
D003583:Cytokinins; D010937:Plant Growth Regulators
Proc Natl Acad Sci U S A. 1976 Feb;73(2):496-500
1061149
Nature. 1975 May 29;255(5507):401-2
1128700
Proc Natl Acad Sci U S A. 1969 Feb;62(2):349-56
4240333
Nat New Biol. 1973 Jul 4;244(131):29-30
4515911
Prog Exp Tumor Res. 1972;15:76-92
4552169
Science. 1973 Jun 29;180(4093):1366-8
4709873
C R Acad Sci Hebd Seances Acad Sci D. 1969 Jan 13;268(2):318-21
4976028
Proc Natl Acad Sci U S A. 1966 Jan;55(1):106-14
5220858
Proc Natl Acad Sci U S A. 1966 Jan;55(1):66-73
5328643
Dev Biol. 1971 Feb;24(2):287-300
5553369
Exp Cell Res. 1965 Oct;40(1):85-95
5838953
Symp Soc Exp Biol. 1957;11:132-42
13486468
J Gen Physiol. 1960 Mar;43:841-51
13799400
Proc Natl Acad Sci U S A. 1958 Apr;44(4):344-9
16590203
Proc Natl Acad Sci U S A. 1958 Jul 15;44(7):712-7
16590265
Proc Natl Acad Sci U S A. 1959 Jul;45(7):932-8
16590486
Proc Natl Acad Sci U S A. 1973 Mar;70(3):658-60
16592068
Proc Natl Acad Sci U S A. 1973 Sep;70(9):2660-2
16592110
Proc Natl Acad Sci U S A. 1976 Oct;73(10):3562-4
16592354
Plant Physiol. 1972 Nov;50(5):616-21
16658228