Some properties of chromatin synthesized by mouse-L-cells temperature-sensitive in DNA replication.

Sheinin, Rose; Darragh, Pamela; Dubsky, Margaret

doi:10.1016/s0021-9258(17)38192-9

Cited by 15 publications

(2 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At later times, semiconservative DNA synthesis is replaced by repair replication (41,42). Temperature inactivation of DNA synthesis is followed within 6 h by inhibition of de novo synthesis of chromatin histones although preformed histones are fully conserved (44). Protoplasmic growth is not blocked and continues over several days, leading eventually to at least a doubling of cell and nuclear volume.…”

Section: Discussionmentioning

confidence: 99%

Structure of interphase nuclei in relation to the cell cycle. Chromatin organization in mouse L cells temperature-sensitive for DNA replication

Setterfield¹,

Sheinin²,

Dardick³

et al. 1978

The Journal of Cell Biology

View full text Add to dashboard Cite

Mutant lines of mouse L cells, TS A1S9, and TS C1, show temperature-sensitive (TS) DNA synthesis and cell division when shifted from 34 ~ to 38.5~ With TS A1S9 the decline in DNA synthesis begins after 6-8 h at 38.5~ and is most marked at about 24 h. Most cells in S, G~, or M at temperature upshift complete one mitosis and accumulate in the subsequent interphase at G~ or early S as a result of expression of a primary defect, failure of elongation of newly made small DNA fragments. Heat inactivation of TS C1 cells is more rapid; they fail to complete the interphase in progress at temperature upshift and accumulate at late S or G2. Inhibition of both cell types is reversible on return to 34~ Cell and nuclear growth continues during inhibition of replication.Expression of both TS mutations leads to a marked change in gross organization of chromatin as revealed by electron microscopy. Nuclei of wild-type cells at 34 ~ and 38.5~ and mutant cells at 34~ show a range of aggregation of condensed chromatin from small dispersed bodies to large discrete clumps, with the majority in an intermediate state. In TS cells at 38.5~ condensed chromatin bodies in the central nuclear region become disaggregated into small clumps dispersed through the nucleus. Morphometric estimation of volume of condensed chromatin indicates that this process is not due to complete decondensation of ehromatin fibrils, but rather involves dispersal of large condensed chromatin bodies into finer aggregates and loosening of fibrils within the aggregates. The dispersed condition is reversed in nuclei which resume DNA synthesis when TS cells are downshifted from 38.5 ~ to 34~ The morphological observations are consistent with the hypothesis that condensed chromatin normally undergoes an ordered cycle of transient, localized disaggregation and reaggregation associated with replication. In temperature-inactivated mutants, normal progressive disaggregation presumably occurs, but subsequent lack of chromatin replication prevents reaggregation. 246J, CELL BIOLOGY t~ The Rockefeller University Press.

show abstract

Section: Discussionmentioning

confidence: 99%

Structure of interphase nuclei in relation to the cell cycle. Chromatin organization in mouse L cells temperature-sensitive for DNA replication

Setterfield¹,

Sheinin²,

Dardick³

et al. 1978

The Journal of Cell Biology

View full text Add to dashboard Cite

show abstract

“…The kinetics of heat inactivation of DNA synthesis in ts 2 cultures resemble, in a general way, those observed with dna,s/S,s mouse L-cells [cf. Sheinin (1976Sheinin ( , 1980, Sheinin & Guttman (1977), Setterfield et al (1978), Sheinin et al ( , 1978a, Guttman & Sheinin (1979), Sheinin & Lewis (1980), and Ganz & Sheinin (1983)]. Any DNA synthesis carried out by such cells incubated at the npt for an elapse time equivalent to two generation periods is effected by normal semiconservative, semidiscontinuous replication.…”

Section: Discussionmentioning

confidence: 99%

DNA synthesis in Balb/C-3T3 ts 2 cells is restricted by a temperature-sensitive function of late G1 phase

Sheinin¹,

Mirjah²,

Dubsky³

et al. 1986

Biochemistry

View full text Add to dashboard Cite

ts 2 BalB/C-3T3 mouse fibroblasts are cdc mutants, which arrest late in G1, at or near the G1/S traverse, upon full expression of the heat-sensitive lesion. The kinetics of temperature inhibition of DNA synthesis in logarithmically growing cultures reveal three stages of heat inactivation. During the first generation time equivalent, normal semiconservative, semidiscontinuous replication proceeds but is reduced as cells exit and do not reenter S phase. During a second such period, a minimal rate of normal DNA synthesis is maintained. Thereafter, as the cells move into a third aborted cell division cycle, the rate of DNA synthesis increases. However, all semiconservative synthesis is then replaced by DNA repair replication. Temperature inactivation of the ts 2 protein results in shutdown of nuclear DNA synthesis. In contrast, normal replication of mitochondrial DNA proceeds at control rate throughout the first stage of temperature inactivation. Synthesis of this organellar genome is quantitatively reduced as the cells move into the second phase of heat inhibition. Titration of chromatin-bound DNA with ethidium bromide revealed that wild-type cells exhibit a changing DNA topology as the temperature is raised. Temperature-inactivated ts 2 cells behave as though their DNA has been topologically frozen in the configuration of control cells at or near entry into S phase.

show abstract

Protein synthesis and degradation during expression of the temperature‐sensitive defect in ts A1S9 mouse L‐cells

Sparkuhl

Sheinin

1980

Journal Cellular Physiology

View full text Add to dashboard Cite

The involvement of altered protein metabolism in the expression of the temperature-sensitive (ts) pleiotropic phenotype of ts A1S9 cells was investigated. Cells are ts in growth and DNA replication. They undergo decondensation of their heterochromatin, interruptions of chromatin synthesis, and changes in cell size and morphology at the non-permissive temperature (npt) of 38.5 degrees C. Whereas the rates of incorporation of 3H-leucine, 35S-methionine, and 3H-fucose into proteins were unaffected at 38.5 degrees C, net protein accumulation was greatly reduced. This imbalance resulted from a rapid increase in the rate of protein degradation at the npt. Enhancement of protein degradation was detected within 2-4 hours after temperature upshift and constitutes the earliest metabolic alteration thus far observed during expression of the temperature-sensitive phenotype. The average half-life of proteins performed in ts A1S9 cells at 34 degrees C was decreased four-fold at the npt, and all major cytoplasmic proteins were affected equally. Enhanced protein degradation at the npt was shown to be sensitive to cycloheximide, ammonia, chloroquine, and vinblastine at concentrations that did not affect the basal protein degradation of normally cycling cells. Increased protein degradation at 38.5 degrees C did not involve an equivalent increase in total cellular protease activity. The data obtained are compatible with a model that suggests that temperature inactivation of the ts A1S9 gene product results in activation of a lysosome-mediated mechanism for the rapid degradation of cytoplasmic proteins.

show abstract

Some properties of chromatin synthesized by mouse-L-cells temperature-sensitive in DNA replication.

Cited by 15 publications

References 28 publications

Structure of interphase nuclei in relation to the cell cycle. Chromatin organization in mouse L cells temperature-sensitive for DNA replication

Structure of interphase nuclei in relation to the cell cycle. Chromatin organization in mouse L cells temperature-sensitive for DNA replication

DNA synthesis in Balb/C-3T3 ts 2 cells is restricted by a temperature-sensitive function of late G1 phase

Protein synthesis and degradation during expression of the temperature‐sensitive defect in ts A1S9 mouse L‐cells

Contact Info

Product

Resources

About