TY - JOUR
T1 - Accumulation, activity and localization of cell cycle regulatory proteins and the chloroplast division protein FtsZ in the alga Scenedesmus quadricauda under inhibition of nuclear DNA replication
AU - Vítová, Milada
AU - Hendrychová, Jana
AU - Čížková, Mária
AU - Cepák, Vladislav
AU - Umen, James G.
AU - Zachleder, Vilém
AU - Bišová, Kateřina
N1 - Funding Information:
The Grant Agency of the Academy of Sciences of the Czech Republic (grant Nos. B5020305, A500200614 and A600200701); the Grant Agency of the Czech Republic (grant No. 204/06/0102]; the Institutional Research Concepts (Nos. AV0Z50200510 and AV0Z60050516) funded by the Academy of Sciences of the Czech Republic.
PY - 2008/12
Y1 - 2008/12
N2 - Synchronized cultures of the green alga Scenedesmus quadricauda were grown in the absence (untreated cultures) or in the presence (FdUrd-treated cultures) of 5-fluorodeoxyuridine, the specific inhibitor of nuclear DNA replication. The attainment of commitment points, at which the cells become committed to nuclear DNA replication, mitosis and cellular division, and the course of committed processes themselves were determined for cell cycle characterization. FdUrd-treated cultures showed nearly unaffected growth and attainment of the commitment points, while DNA replication(s), nuclear division(s) and protoplast fission(s) were blocked. Interestingly, the FdUrd-treated cells possessed a very high mitotic histone H1 kinase activity in the absence of any nuclear division(s). Compared with the untreated cultures, the kinase activity as well as mitotic cyclin B accumulation increased continuously to high values without any oscillation. Division of chloroplasts was not blocked but occurred delayed and over a longer time span than in the untreated culture. The FtsZ protein level in the FdUrd-treated culture did not exceed the level in the untreated culture, but rather, in contrast to the untreated culture, remained elevated. FtsZ structures were both localized around pyrenoids and spread inside of the chloroplast in the form of spots and mini-rings. The abundance and localization of the FtsZ protein were comparable in untreated and FdUrd-treated cells until the end of the untreated cell cycle. However, in the inhibitor-treated culture, the signal did not decrease and was localized in intense spots surrounding the chloroplast/cell perimeter; this was in agreement with both the elevated protein level and persisting chloroplast division.
AB - Synchronized cultures of the green alga Scenedesmus quadricauda were grown in the absence (untreated cultures) or in the presence (FdUrd-treated cultures) of 5-fluorodeoxyuridine, the specific inhibitor of nuclear DNA replication. The attainment of commitment points, at which the cells become committed to nuclear DNA replication, mitosis and cellular division, and the course of committed processes themselves were determined for cell cycle characterization. FdUrd-treated cultures showed nearly unaffected growth and attainment of the commitment points, while DNA replication(s), nuclear division(s) and protoplast fission(s) were blocked. Interestingly, the FdUrd-treated cells possessed a very high mitotic histone H1 kinase activity in the absence of any nuclear division(s). Compared with the untreated cultures, the kinase activity as well as mitotic cyclin B accumulation increased continuously to high values without any oscillation. Division of chloroplasts was not blocked but occurred delayed and over a longer time span than in the untreated culture. The FtsZ protein level in the FdUrd-treated culture did not exceed the level in the untreated culture, but rather, in contrast to the untreated culture, remained elevated. FtsZ structures were both localized around pyrenoids and spread inside of the chloroplast in the form of spots and mini-rings. The abundance and localization of the FtsZ protein were comparable in untreated and FdUrd-treated cells until the end of the untreated cell cycle. However, in the inhibitor-treated culture, the signal did not decrease and was localized in intense spots surrounding the chloroplast/cell perimeter; this was in agreement with both the elevated protein level and persisting chloroplast division.
KW - Chloroplast fission
KW - Cyclin-dependent kinase
KW - Fluorodeoxyuridine
KW - FtsZ protein
KW - Mitotic cyclin B
KW - Scenedesmus quadricauda
UR - http://www.scopus.com/inward/record.url?scp=57749178795&partnerID=8YFLogxK
U2 - 10.1093/pcp/pcn162
DO - 10.1093/pcp/pcn162
M3 - Article
C2 - 18977763
AN - SCOPUS:57749178795
SN - 0032-0781
VL - 49
SP - 1805
EP - 1817
JO - Plant and Cell Physiology
JF - Plant and Cell Physiology
IS - 12
ER -