The function of the chicken p34CDC2 protein kinase in fission yeast is cold sensitive for cell cycle progression through the G1 phase and temperature sensitive for traversal of mitosis

1999 ◽  
Vol 261 (4-5) ◽  
pp. 716-724
Author(s):  
N. Schmitz
2007 ◽  
Vol 282 (46) ◽  
pp. 33459-33465 ◽  
Author(s):  
Satoshi Tsutsumi ◽  
Reiko Sugiura ◽  
Yan Ma ◽  
Hideki Tokuoka ◽  
Kazuki Ohta ◽  
...  

Inosine (I) at position 34 (wobble position) of tRNA is formed by the hydrolytic deamination of a genomically encoded adenosine (A). The enzyme catalyzing this reaction, termed tRNA A:34 deaminase, is the heterodimeric Tad2p/ADAT2·Tad3p/ADAT3 complex in eukaryotes. In budding yeast, deletion of each subunit is lethal, indicating that the wobble inosine tRNA modification is essential for viability; however, most of its physiological roles remain unknown. To identify novel cell cycle mutants in fission yeast, we isolated the tad3-1 mutant that is allelic to the tad3+ gene encoding a homolog of budding yeast Tad3p. Interestingly, the tad3-1 mutant cells principally exhibited cell cycle-specific phenotype, namely temperature-sensitive and irreversible cell cycle arrest both in G1 and G2. Further analyses revealed that in the tad3-1 mutant cells, the S257N mutation that occurred in the catalytically inactive Tad3 subunit affected its association with catalytically active Tad2 subunit, leading to an impairment in the A to I conversion at position 34 of tRNA. In tad3-1 mutant cells, the overexpression of the tad3+ gene completely suppressed the decreased tRNA inosine content. Notably, the overexpression of the tad2+ gene partially suppressed the temperature-sensitive phenotype and the decreased tRNA inosine content, indicating that the tad3-1 mutant phenotype is because of the insufficient I34 formation of tRNA. These results suggest that the wobble inosine tRNA modification is essential for cell cycle progression in the G1/S and G2/M transitions in fission yeast.


2010 ◽  
Vol 9 (10) ◽  
pp. 1418-1431 ◽  
Author(s):  
Emma L. Turner ◽  
Mackenzie E. Malo ◽  
Marnie G. Pisclevich ◽  
Megan D. Dash ◽  
Gerald F. Davies ◽  
...  

ABSTRACT The anaphase-promoting complex (APC), a large evolutionarily conserved ubiquitin ligase complex, regulates cell cycle progression through mitosis and G1. Here, we present data suggesting that APC-dependent cell cycle progression relies on a specific set of posttranslational histone-modifying enzymes. Multiple APC subunit mutants were impaired in total and modified histone H3 protein content. Acetylated H3K56 (H3K56Ac) levels were as reduced as those of total H3, indicating that loading histones with H3K56Ac is unaffected in APC mutants. However, under restrictive conditions, H3K9Ac and dimethylated H3K79 (H3K79me2) levels were more greatly reduced than those of total H3. In a screen for histone acetyltransferase (HAT) and histone deacetylase (HDAC) mutants that genetically interact with the apc5 CA (chromatin assembly) mutant, we found that deletion of GCN5 or ELP3 severely hampered apc5 CA temperature-sensitive (ts) growth. Further analyses showed that (i) the elp3Δ gcn5Δ double mutant ts defect was epistatic to that observed in apc5 CA cells; (ii) gcn5Δ and elp3Δ mutants accumulate in mitosis; and (iii) turnover of the APC substrate Clb2 is not impaired in elp3Δ gcn5Δ cells. Increased expression of ELP3 and GCN5, as well as genes encoding the HAT Rtt109 and the chromatin assembly factors Msi1 and Asf1, suppressed apc5 CA defects, while increased APC5 expression partially suppressed elp3Δ gcn5Δ growth defects. Finally, we demonstrate that Gcn5 is unstable during G1 and following G1 arrest and is stabilized in APC mutants. We present our working model in which Elp3/Gcn5 and the APC work together to facilitate passage through mitosis and G1. To progress into S, we propose that at least Gcn5 must then be targeted for degradation in an APC-dependent fashion.


2013 ◽  
Vol 24 (12) ◽  
pp. 1872-1881 ◽  
Author(s):  
Lin Deng ◽  
James B. Moseley

Cell cycle progression is coupled to cell growth, but the mechanisms that generate growth-dependent cell cycle progression remain unclear. Fission yeast cells enter into mitosis at a defined size due to the conserved cell cycle kinases Cdr1 and Cdr2, which localize to a set of cortical nodes in the cell middle. Cdr2 is regulated by the cell polarity kinase Pom1, suggesting that interactions between cell polarity proteins and the Cdr1-Cdr2 module might underlie the coordination of cell growth and division. To identify the molecular connections between Cdr1/2 and cell polarity, we performed a comprehensive pairwise yeast two-hybrid screen. From the resulting interaction network, we found that the protein Skb1 interacted with both Cdr1 and the Cdr1 inhibitory target Wee1. Skb1 inhibited mitotic entry through negative regulation of Cdr1 and localized to both the cytoplasm and a novel set of cortical nodes. Skb1 nodes were distinct structures from Cdr1/2 nodes, and artificial targeting of Skb1 to Cdr1/2 nodes delayed entry into mitosis. We propose that the formation of distinct node structures in the cell cortex controls signaling pathways to link cell growth and division.


2003 ◽  
Vol 8 (4) ◽  
pp. 311-324 ◽  
Author(s):  
Koichi Kitamura ◽  
Keiko Mizuno ◽  
Akiko Etoh ◽  
Yoshiko Akita ◽  
Akitomo Miyamoto ◽  
...  

1993 ◽  
Vol 13 (6) ◽  
pp. 3577-3587 ◽  
Author(s):  
E A Musgrove ◽  
J A Hamilton ◽  
C S Lee ◽  
K J Sweeney ◽  
C K Watts ◽  
...  

Cyclins and proto-oncogenes including c-myc have been implicated in eukaryotic cell cycle control. The role of cyclins in steroidal regulation of cell proliferation is unknown, but a role for c-myc has been suggested. This study investigated the relationship between regulation of T-47D breast cancer cell cycle progression, particularly by steroids and their antagonists, and changes in the levels of expression of these genes. Sequential induction of cyclins D1 (early G1 phase), D3, E, A (late G1-early S phase), and B1 (G2 phase) was observed following insulin stimulation of cell cycle progression in serum-free medium. Transient acceleration of G1-phase cells by progestin was also accompanied by rapid induction of cyclin D1, apparent within 2 h. This early induction of cyclin D1 and the ability of delayed administration of antiprogestin to antagonize progestin-induced increases in both cyclin D1 mRNA and the proportion of cells in S phase support a central role for cyclin D1 in mediating the mitogenic response in T-47D cells. Compatible with this hypothesis, antiestrogen treatment reduced the expression of cyclin D1 approximately 8 h before changes in cell cycle phase distribution accompanying growth inhibition. In the absence of progestin, antiprogestin treatment inhibited T-47D cell cycle progression but in contrast did not decrease cyclin D1 expression. Thus, changes in cyclin D1 gene expression are often, but not invariably, associated with changes in the rate of T-47D breast cancer cell cycle progression. However, both antiestrogen and antiprogestin depleted c-myc mRNA by > 80% within 2 h. These data suggest the involvement of both cyclin D1 and c-myc in the steroidal control of breast cancer cell cycle progression.


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