In:
Journal of Cell Science, The Company of Biologists, Vol. 41, No. 1 ( 1980-02-01), p. 105-113
Abstract:
Endogenous RNA polymerase activity of isolated nuclei from Physarum polycephalum was determined at high (400 mM KC1) and low (5 – 100 rπM KC1) ionic strength. The activity of RNA polymerase B (α-amanitin-sensitive UMP incorporation) and of RNA polymerase A (plus C) (α-amanitin-resistant UMP incorporation) was compared in accurately sized nuclear samples derived from macroplasmodia at distinct points of the mitotic cycle. Minimum total RNA polymerase activity was detected in metaphase nuclei. A constant level of RNA polymerase B activity was detected at all other stages of the mitotic cycle, if nuclei were assayed at high ionic strength. However, a high level in S-phase, a low level in G2-phase and again a high level in early prophase were measured, if nuclei were assayed at low ionic strength. Inhibition of DNA synthesis by hydroxyurea in vivo had a selective and drastic effect on in vitro RNA polymerase activity of isolated nuclei derived from S-phase plasmodia, yielding up to 100% inhibition in early S-phase.
Type of Medium:
Online Resource
ISSN:
0021-9533
,
1477-9137
DOI:
10.1242/jcs.41.1.105
Language:
English
Publisher:
The Company of Biologists
Publication Date:
1980
detail.hit.zdb_id:
219171-4
detail.hit.zdb_id:
1483099-1
SSG:
12
