Replication-coupled modulation of early replicating chromatin domains detected by anti-actin antibody.
Evidence is presented for the reversible, cold-dependent immunofluorescence detection of the epitope (hereafter referred to as epiC), recognized by a monoclonal anti-actin antibody in diploid human fibroblast cell nuclei and mitotic chromosomes. The nuclear/chromosomal epiC was detected in a cell cycle window beginning in early S phase and extending through S phase, G(2) phase, mitosis until early G(1) phase of the subsequent daughter cells. A small but significant level of co-localization was measured between the nuclear epiC and active sites of DNA replication in early S phase. The level of co-localization was strikingly enhanced beginning approximately 1 h after the initial labeling of early S phase replicating chromatin domains. In contrast, epiC did not co-localize with late S phase replicated chromatin either during DNA replication or at any other time in the cell cycle. We propose a replication-coupled modulation of early S phase replicated chromatin domains that is detected by the chromatin epiC positivity, persists on the chromatin domains from early S until early G(1) of the next cell generation, and may be involved in the regulation and/or coordination of replicational and transcriptional processes during the cell cycle. Further studies will be required to resolve the possible role of nuclear actin in this modulation process.
Fidlerová
Helena
H
Department of Cell Biology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 1st Faculty of Medicine, Charles University in Prague, Albertov 4, 128 00 Prague 2, Czech Republic. hfid@fl.cuni.cz
Masata
Martin
M
Malínský
Jan
J
Fialová
Markéta
M
Cvacková
Zuzana
Z
Louzecká
Alena
A
Koberna
Karel
K
Berezney
Ronald
R
Raska
Ivan
I
D000199:Actins / Q000276:immunology*; D015153:Blotting, Western; D002478:Cells, Cultured; D002843:Chromatin / Q000737:chemistry*; D004261:DNA Replication; D016193:G1 Phase; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D016196:S Phase
D000199:Actins; D002843:Chromatin