scholarly journals The Function of Lipin in the Wing Development of Drosophila melanogaster

2019 ◽  
Vol 20 (13) ◽  
pp. 3288 ◽  
Author(s):  
Tran Duy Binh ◽  
Tuan L. A. Pham ◽  
Taisei Nishihara ◽  
Tran Thanh Men ◽  
Kaeko Kamei
Keyword(s):  
Dna Damage ◽  
Drosophila Melanogaster ◽  
Imaginal Disc ◽  
Cell Cycle Progression ◽  
Apoptotic Cell ◽  
Wing Imaginal Disc ◽  
Wing Development ◽  
Cycle Progression ◽  
Evolutionarily Conserved

Lipin is evolutionarily conserved from yeast to mammals. Although its roles in lipid metabolism in adipocyte tissue, skeletal muscle, and the liver, and as a transcriptional co-activator are known, its functions during development are still under investigation. In this study, we analyzed the role of Drosophila lipin (dLipin) in development. Specifically, we showed that the tissue-selective knockdown of dLipin in the wing pouch led to an atrophied wing. Elevated DNA damage was observed in the wing imaginal disc of dLipin-knockdown flies. dLipin dysfunction induced accumulation of cells in S phase and significantly reduced the number of mitotic cells, indicating DNA damage-induced activation of the G2/M checkpoint. Reduced expression of cyclin B, which is critical for the G2 to M transition, was observed in the margin of the wing imaginal disc of dLipin-knockdown flies. The knockdown of dLipin led to increased apoptotic cell death in the wing imaginal disc. Thus, our results suggest that dLipin is involved in DNA replication during normal cell cycle progression in wing development of Drosophila melanogaster.

scholarly journals Critical role of SMG7 in activation of the ATR-CHK1 axis in response to genotoxic stress

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kathleen Ho ◽  
Hongwei Luo ◽  
Wei Zhu ◽  
Yi Tang
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Replication ◽  
Cell Cycle Progression ◽  
Critical Role ◽  
Genotoxic Stress ◽  
Dna Damage Checkpoint ◽  
Cycle Progression ◽  
Essential Step

AbstractCHK1 is a crucial DNA damage checkpoint kinase and its activation, which requires ATR and RAD17, leads to inhibition of DNA replication and cell cycle progression. Recently, we reported that SMG7 stabilizes and activates p53 to induce G1 arrest upon DNA damage; here we show that SMG7 plays a critical role in the activation of the ATR-CHK1 axis. Following genotoxic stress, SMG7-null cells exhibit deficient ATR signaling, indicated by the attenuated phosphorylation of CHK1 and RPA32, and importantly, unhindered DNA replication and fork progression. Through its 14-3-3 domain, SMG7 interacts directly with the Ser635-phosphorylated RAD17 and promotes chromatin retention of the 9-1-1 complex by the RAD17-RFC, an essential step to CHK1 activation. Furthermore, through maintenance of CHK1 activity, SMG7 controls G2-M transition and facilitates orderly cell cycle progression during recovery from replication stress. Taken together, our data reveals SMG7 as an indispensable signaling component in the ATR-CHK1 pathway during genotoxic stress response.

scholarly journals Non-SMC condensin I complex subunit H mediates mature chromosome condensation and DNA damage in pancreatic cancer cells

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jae Hyeong Kim ◽  
Yuna Youn ◽  
Kyung-Tae Kim ◽  
Gyubeom Jang ◽  
Jin-Hyeok Hwang
Keyword(s):  
Cell Cycle ◽  
Pancreatic Cancer ◽  
Dna Damage ◽  
Cell Death ◽  
Cell Cycle Progression ◽  
Apoptotic Cell ◽  
Chromosome Condensation ◽  
Parp Cleavage ◽  
Pancreatic Cancer Cells

AbstractNon-SMC condensin I complex subunit H (NCAPH) is a vital gene associated with chromosome stability and is required for proper chromosome condensation and segregation. However, the mechanisms through which NCAPH affects pancreatic cancer (PC) and its molecular function remain unclear. In this study, we examined the role of NCAPH in PC cells. Our results showed that NCAPH was overexpressed in clinical PC specimens (GEPIA) and cell lines. In addition, in NCAPH-knockdown cells, colony formation and proliferation were inhibited, and the cell cycle was arrested at the S and G2/M phases owing to failure of mature chromosome condensation (MCC) in poorly condensed chromosomes. Increased cell death in NCAPH-knockdown cells was found to help initiate apoptosis through the activation of caspase-3 and PARP cleavage. Furthermore, NCAPH-knockdown cells showed an increase in chromosomal aberrations and DNA damage via activation of the DNA damage response (Chk1/Chk2) signaling pathways. These data demonstrated that NCAPH played an important role in cell cycle progression and DNA damage by maintaining chromosomal stability through progression of MCC from poorly condensed chromosomes. Ultimately, NCAPH knockdown induced apoptotic cell death, which was partially mediated by caspase-dependent pathways. These findings highlight the potential role of NCAPH as a therapeutic target for PC.

Phenotypic characterization ofDrosophila idamutants: defining the role of APC5 in cell cycle progression

2002 ◽  
Vol 115 (5) ◽  
pp. 949-961 ◽  
Author(s):  
A. M. Bentley ◽  
Byron C. Williams ◽  
Michael L. Goldberg ◽  
Andrew J. Andres
Keyword(s):  
Imaginal Disc ◽  
Cell Cycle Progression ◽  
Cell Types ◽  
Cyclin B ◽  
Phenotypic Characterization ◽  
Anaphase Promoting Complex ◽  
Cycle Progression ◽  
Disc Cells ◽  
A Subunit

We have cloned and characterized the ida gene that is required for proliferation of imaginal disc cells during Drosophila development. IDA is homologous to APC5, a subunit of the anaphase-promoting complex(APC/cyclosome). ida mRNA is detected in most cell types throughout development, but it accumulates to its highest levels during early embryogenesis. A maternal component of IDA is required for the production of eggs and viable embryos. Homozygous ida mutants display mitotic defects: they die during prepupal development, lack all mature imaginal disc structures, and have abnormally small optic lobes. Cytological observations show that ida mutant brains have a high mitotic index and many imaginal cells contain an aneuploid number of aberrant overcondensed chromosomes. However, cells are not stalled in metaphase, as mitotic stages in which chromosomes are orientated at the equatorial plate are never observed. Interestingly, some APC/C-target substrates such as cyclin B are not degraded in ida mutants, whereas others controlling sister-chromatid separation appear to be turned over. Taken together, these results suggest a model in which IDA/APC5 controls regulatory subfunctions of the anaphase-promoting complex.

scholarly journals A methylation-phosphorylation switch determines Plk1 kinase activity and function in DNA damage repair

2019 ◽  
Vol 5 (3) ◽  
pp. eaau7566 ◽  
Author(s):  
Weizhe Li ◽  
Hong-Yan Wang ◽  
Xiaolu Zhao ◽  
Hongguo Duan ◽  
Binghua Cheng ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Critical Role ◽  
Dna Damage Repair ◽  
Cycle Progression ◽  
Sister Chromatids ◽  
Damage Repair ◽  
And Function

Polo-like kinase 1 (Plk1) is a crucial regulator of cell cycle progression; but the mechanism of regulation of Plk1 activity is not well understood. We present evidence that Plk1 activity is controlled by a balanced methylation and phosphorylation switch. The methyltransferase G9a monomethylates Plk1 at Lys209, which antagonizes phosphorylation of T210 to inhibit Plk1 activity. We found that the methyl-deficient Plk1 mutant K209A affects DNA replication, whereas the methyl-mimetic Plk1 mutant K209M prolongs metaphase-to-anaphase duration through the inability of sister chromatids separation. We detected accumulation of Plk1 K209me1 when cells were challenged with DNA damage stresses. Ablation of K209me1 delays the timely removal of RPA2 and RAD51 from DNA damage sites, indicating the critical role of K209me1 in guiding the machinery of DNA damage repair. Thus, our study highlights the importance of a methylation-phosphorylation switch of Plk1 in determining its kinase activity and functioning in DNA damage repair.

scholarly journals DNA Damage Triggers p21WAF1-dependent Emi1 Down-Regulation That Maintains G2 Arrest

2009 ◽  
Vol 20 (7) ◽  
pp. 1891-1902 ◽  
Author(s):  
Jinho Lee ◽  
Jin Ah Kim ◽  
Valerie Barbier ◽  
Arun Fotedar ◽  
Rati Fotedar
Keyword(s):  
Dna Damage ◽  
Cell Cycle Progression ◽  
Control Cell ◽  
Anaphase Promoting Complex ◽  
Checkpoint Control ◽  
G2 Arrest ◽  
Down Regulation ◽  
Cycle Progression ◽  
M Phase

Several regulatory proteins control cell cycle progression. These include Emi1, an anaphase-promoting complex (APC) inhibitor whose destruction controls progression through mitosis to G1, and p21WAF1, a cyclin-dependent kinase (CDK) inhibitor activated by DNA damage. We have analyzed the role of p21WAF1 in G2-M phase checkpoint control and in prevention of polyploidy after DNA damage. After DNA damage, p21+/+ cells stably arrest in G2, whereas p21−/− cells ultimately progress into mitosis. We report that p21 down-regulates Emi1 in cells arrested in G2 by DNA damage. This down-regulation contributes to APC activation and results in the degradation of key mitotic proteins including cyclins A2 and B1 in p21+/+ cells. Inactivation of APC in irradiated p21+/+ cells can overcome the G2 arrest. siRNA-mediated Emi1 down-regulation prevents irradiated p21−/− cells from entering mitosis, whereas concomitant down-regulation of APC activity counteracts this effect. Our results demonstrate that Emi1 down-regulation and APC activation leads to stable p21-dependent G2 arrest after DNA damage. This is the first demonstration that Emi1 regulation plays a role in the G2 DNA damage checkpoint. Further, our work identifies a new p21-dependent mechanism to maintain G2 arrest after DNA damage.

PTTG has a Dual Role of Promotion-Inhibition in the Development of Pituitary Adenomas

2019 ◽  
Vol 26 (11) ◽  
pp. 800-818
Author(s):  
Zujian Xiong ◽  
Xuejun Li ◽  
Qi Yang
Keyword(s):  
Cell Cycle ◽  
Pituitary Adenoma ◽  
Pituitary Adenomas ◽  
Cell Cycle Progression ◽  
Key Factors ◽  
Cycle Progression ◽  
Sister Chromatids ◽  
Regulation Of Cell Cycle ◽  
Late Stages

Pituitary Tumor Transforming Gene (PTTG) of human is known as a checkpoint gene in the middle and late stages of mitosis, and is also a proto-oncogene that promotes cell cycle progression. In the nucleus, PTTG works as securin in controlling the mid-term segregation of sister chromatids. Overexpression of PTTG, entering the nucleus with the help of PBF in pituitary adenomas, participates in the regulation of cell cycle, interferes with DNA repair, induces genetic instability, transactivates FGF-2 and VEGF and promotes angiogenesis and tumor invasion. Simultaneously, overexpression of PTTG induces tumor cell senescence through the DNA damage pathway, making pituitary adenoma possessing the potential self-limiting ability. To elucidate the mechanism of PTTG in the regulation of pituitary adenomas, we focus on both the positive and negative function of PTTG and find out key factors interacted with PTTG in pituitary adenomas. Furthermore, we discuss other possible mechanisms correlate with PTTG in pituitary adenoma initiation and development and the potential value of PTTG in clinical treatment.

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