Version 2 2019-08-07, 16:25Version 2 2019-08-07, 16:25
Version 1 2019-08-07, 16:04Version 1 2019-08-07, 16:04
figure
posted on 2019-08-07, 16:25authored byChi-Fu Chen, Thomas J. Pohl, Angela Chan, Joshua S. Slocum, Virginia A. Zakian
two
common features of centromeres are their transcription into non-coding RNAs
(cen-RNA) and their assembly into nucleosomes that contain a
centromere-specific histone H3 (cenH3). Here we show that Saccharomyces cerevisiae cen-RNA was present in low amounts in wild
type cells, and its appearance was tightly cell cycle regulated, appearing and
disappearing in a narrow window in S phase after centromere replication. In
cells lacking Cbf1, a centromere binding protein, cen-RNA was 5-12 times more
abundant throughout the cell cycle. In
wild type cells, cen-RNA appearance occurred at the same time as loss of Cbf1’s
centromere binding, arguing that the physical presence of Cbf1 inhibits cen-RNA
production. Binding of the Pif1 DNA helicase, which happens in mid-late S
phase, occurred at about the same time as Cbf1 loss from the centromere,
suggesting that Pif1 may facilitate this loss by its known ability to displace
proteins from DNA. cen-RNAs were more abundant in rnh1Δ cells but only
in mid-late S phase. However, fork pausing at centromeres was not elevated in rnh1Δ
cells but rather was due to centromere binding proteins, including Cbf1. Strains
with increased cen-RNA lost centromere plasmids at elevated rates. In cbf1Δ
cells, where both the levels and cell cycle regulated appearance of cen-RNA
were disrupted, the timing and levels of CenH3 centromere binding were
perturbed. Thus, cen-RNAs are highly regulated and disruption of this
regulation correlates with changes in centromere structure and function.
History
Article title
Saccharomyces cerevisiae Centromere RNA Is Negatively Regulated by Cbf1 and Its Unscheduled Synthesis Impacts CenH3 Binding