Genetic analysis of the Drosophila cdc2 homolog

Development ◽  
1993 ◽  
Vol 117 (1) ◽  
pp. 219-232 ◽  
Author(s):  
B. Stern ◽  
G. Ried ◽  
N.J. Clegg ◽  
T.A. Grigliatti ◽  
C.F. Lehner

We have identified mutations in the Drosophila cdc2 gene. The recessive lethality of these mutant alleles was rescued after P-element-mediated transformation with a genomic cdc2 fragment. Sequence analysis of amorphic alleles revealed non-conservative exchanges in evolutionary conserved positions. These alleles caused lethality at the larval-pupal interphase due to the absence of imaginal tissues. Embryonic lethality resulted when the maternal Dm cdc2 contribution was reduced through the use of a temperature-sensitive allele. Dm cdc2 function, therefore, is essential for cell proliferation throughout development. Dm cdc2 function is clearly required for mitosis, but no evidence for a requirement in S-phase was obtained. The reversible block of the mitotic proliferation which was observed in the PNS of mutant embryos occurred exclusively in the G2-phase. Moreover, while the mitotic proliferation of imaginal cells was blocked in the amorphic mutant larvae, non-imaginal larval cells continued to grow and endoreplicate their DNA. The Dm cdc2 mutant phenotype could neither be rescued with Dm cdc2c (encoding a cdc2-like kinase) nor enhanced by a reduction of the Dm cdc2c gene dose. These results indicate that the Dm cdc2- and Dm cdc2c-kinases control different processes.

1987 ◽  
Vol 7 (1) ◽  
pp. 444-449
Author(s):  
J P Durkin ◽  
J F Whitfield

NRK cells infected with a temperature-sensitive Kirsten sarcoma virus (ts371 KSV) are transformed at 36 degrees C, but are untransformed at 41 degrees C which inactivates the abnormally thermolabile oncogenic p21Ki product of the viral Ki-ras gene. At 41 degrees C, tsKSV-infected NRK cells were arrested in G0/G1 when incubated in serum-free medium, but could then be stimulated to transit G1, replicate DNA, and divide by adding serum at 41 degrees C or dropping the temperature to a p21-activating 36 degrees C without adding serum. When quiescent cells at 41 degrees C were stimulated to transit G1 in serum-free medium by activating p21 at 36 degrees C and then shifted back to the p21-inactivating 41 degrees C in the mid-S phase, they continued replicating DNA but could not transit G2. Reactivating p21 in the G2-arrested cells by once again lowering the temperature to 36 degrees C stimulated a rapid entry into mitosis. By contrast, while serum-stimulated quiescent G0 cells at 41 degrees C replicate DNA and divide, serum did not induce G2-arrested cells to enter mitosis, indicating that serum growth factors may trigger events in the G1 phase that ultimately determine G2 transit. These observations made with the viral ras product suggest that cellular ras proto-oncogene products have a role in G2 transit of normal cells.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 5125-5125
Author(s):  
Cintia Do Couto Mascarenhas ◽  
Anderson Ferreira Cunha ◽  
Ana Flavia Brugnerotto ◽  
Sheley Gambero ◽  
Joao Machado-Neto ◽  
...  

Abstract Abstract 5125 The TOB1 gene is a transcription factor responsible for the transduction of the gene ERBB2. It is a member of a family of cell suppressor proliferation proteins called TOB/BTG1 family; also, this gene operates on the inhibition of neoplastic transformation. The TOB1 gene presents a decreased expression in several types of cancer such as lung, breast, thyroid and stomach cancer. However, the function of this gene in chronic myeloid leukemia (CML) remains unknown. Aiming to evaluate the inhibition of gene TOB1 into BCR-ABL positive cells and trying to elucidate the molecular mechanisms associated with the inhibition of this gene in the CML we proceed to a more detailed study of this gene. The inhibition of this gene in K562 cells was performed using specific lentivirus. The effect of silencing TOB1 in the proliferation of K562 cells was assessed by the MTT assay after 48 hours of culture; in shTOB1 the proliferation was increased in comparison with shControl cells. To evaluate the synergistic effect between the inhibition of kinase tyrosine activity of BCR-ABL and the inhibition of TOB1 we performed a treatment with different concentrations of imatinib (0. 1, 0. 5 and 1μM), but we observed the decrease in cell proliferation of shTOB1 cells to similar levels of shControl cells only at the 1μM concentration. Therefore, the TOB1 silencing increased the proliferation of K562 cells without an additional effect of a treatment with Imatinib. To analyze the clonogenicity, we performed a formation of colonies assay, in methylcellulose, to determine whether silencing TOB1 could cause a change in the clonal growth of positive BCR-ABL cells. There was no significant change in the number of colonies that grew in cell culture shTOB1 compared to shControl cells. These results suggest that silencing TOB1 in K562 cells may not change the clonogenicity. In the assessment of cell cycle, the flow cytometry analysis revealed a significant accumulation of K562 cells in S phase, with consequent reduction of cells in the G2 phase of the cell cycle in cells shTOB1 compared to cells shControl. The TOB1 gene silencing in K562 cells kept the cells in the S phase and prevented the entry of cells in the G2 phase showing that the inhibition of gene TOB1 induced an increase in proliferation of K562 BCR-ABL cells. The level of apoptosis was assessed by flow cytometry after labeling the cells with anexin-V/PI. The Imatinib treatment presented dose-response in the induction of apoptosis as expected. However, a cumulative effect with TOB1 silencing was not observed. Furthermore, the apoptosis was also assessed by assays of caspases 3, 8 and 9, which showed an increase of the caspase activity of shControl cells in relation of the shTOB1 cells, showing that inhibition of this gene also changes the level of apoptosis. These results corroborate the literature data that report the relationship of this tumour suppressor gene in signalling pathways related to angiogenesis, carcinogenesis, apoptosis and metastasis. When we relate the results obtained with the LMC, we can consider the possibility of TOB1 regulation changes be related to modification of important signalling pathways such as AKT, PI3K, STAT3 and STAT5, among others. Furthermore, the inhibition of TOB1 may be related with an increase on the number of BCR-ABL positive cells and subsequent disease progression. In conclusion, this study confirmed literature data showing that TOB1 gene works as a tumour suppressor protein in cells of many types of cancer. From this work we can infer that in CML the expression of this gene is transformed, resulting in changing of the capacity of induction of apoptosis, decrease tumour necrosis and increase cell proliferation. This work was supported by FAPESP and INCT. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 33-34
Author(s):  
Honglei Wang ◽  
Rong Fu ◽  
Hui Liu ◽  
Zhaoyun Liu ◽  
Liyan Li ◽  
...  

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonogenic disease of hematopoietic stem cells. LncRNAs has a wide range of biological functions, including cell differentiation, cell proliferation and substance metabolism. LncRNAs maybe contribute to the proliferation of PNH clones. Methods: CD59- and CD59+ granulocytes and monocytes cells were sorted by FCM and analyzed by RNA sequencing in 5 PNH patients. We focus on the proliferation relative pathway-NF-κB pathway. The mRNAs which FPKM>10 and over 3 patients were chosen to search out the upstream regulation LncRNAs. Then the expression of LncRNAs were detected by qRT-PCR in 30 PNH patients. The highly expressed LncRNA FAM157C was screened out, and analyzed the correlation with clinical index. Finally, we knock-down FAM157C gene in the PIGA knocked out THP-1 cells by lentivirus transfection technique, and observe the cell proliferation, apoptosis to verify its function. Results: Transcription analysis revealed that 742 upregulation LncRNAs and 3276 upregulation mRNAs were identified in CD59- cells (Figure A). The highly expressed NF-κB pathway (Figure B) mRNAs were analysed by co-expression, after that MALAT1, LINC01002, FAM157C, CTD-2530H12.2, XLOC-064331 and XLOC-106677 were concerned with the 8 mRNAs (Figure C). The results showed that the levels of MALAT1 and FAM157C in CD59- cells expression were significantly higher than that of the CD59+ cell in 30 PNH patients (p<0.05). The expression level of MALAT1 and FAM157C were positive correlation with LDH level and CD59- granulated and monocytes cells ratio (Figure D). Lentivirus FAM157C transfection knock-down FAM157C gene expression (90%) in the PIGA knocked out THP-1 cells. The cell proliferation assay results showed that there was no significant change in the cell viability at 24h after transfection. But with the transfection time, the cell proliferation activity showed a decreasing trend. The cell viability of the control group, empty virus group and FAM157C knock-down group were (100±0), (93.75±5.995), (77.49±6.597) and (100±0), (92.795±5.802), (60.47±2.059) after 48h, 72h transfection respectively (p=0.0069, 0.0002) (Figure E). The apoptosis rate of control group, empty virus group and FAM157C knock-down group were (2.483±0.3083)%, (2.926±0.5517)%, (6.256±0.5453)% and (5.593±0.6400)%, (6.723±0.3256)%, (11.30±1.075)% and (9.797±0.3235)%, (10.21±0.3005)%, (18.81±0.5363)% after 24h, 48h, 72h transfection respectively (p=0.0006, 0.0005, < 0.0001). The cell apoptosis experiment showed that apoptosis rate increased after transfection of lentivirus FAM157C (Figure F). The results of cell cycle test showed that the G0/G1 phase of the control group, empty virus group and FAM157C knockdown group were (62.98±1.513)%, (65.95±1.174)% and (70.00±0.2404)%, S phase were (3.825±0.7849)%, (5.920±0.9192)% and (13.47±1.039)%, G2 phase were (32.81±1.612)%, (27.47±1.160)% and (16.54±0.7990)% after transfection of lentivirus FAM157C (p=0.0269, 0.0198, 0.0145) (Figure G). Conclusion: High expressed FAM157C was associated with hemolysis index in PNH, and knock-down it can decrease proliferation ability, induce the apoptosis and the cells were blocked in G0/G1 phase and S phase, indicating FAM157C may be involved in the proliferation of PNH clones. Key words: Paroxysmal Nocturnal Hemoglobinuria, LncRNAs, clone proliferation NF-κB pathway, LncRNA FAM157C Figure Legends Figure A: Volcanic map of differentially expressed LncRNAs and mRNAs, C2 represents CD59- cells, and C1 represents CD59+ cells. Figure B: Scatter plot is a graphical representation of KEGG enrichment analysis results. Figure C: Screening of mRNAs and LncRNAs from NF-κB pathway. Figure D: Correlation analysis between MALAT1 and FAM157C expression and clinical date. Figure E: The cell proliferation assay was examined by CCK-8 kit. Figure F: The Cell apoptosis rate was examined by flow cytometry. Figure G: After FAM157C knockdown, the proportion of cells in G0/G1 phase and S phase increased, while the proportion of cells in G2 phase decreased, and the cells were blocked in G0/G1 phase and S phase. Figure Disclosures No relevant conflicts of interest to declare.


2016 ◽  
Vol 38 (1) ◽  
pp. 368-378 ◽  
Author(s):  
Bo Xu ◽  
Qin Shao ◽  
Kaipeng Xie ◽  
Yuqing Zhang ◽  
Tianyu Dong ◽  
...  

Background/Aims: Papillary thyroid cancer (PTC) is the most common histotype of Thyroid cancer (TC). Here, we detected the differentially expressed lncRNAs in tumor tissues and non-tumor tissues of PTC patients by lncRNA microarrays, and explored the function and molecular mechanisms of lncRNAs in the pathogenesis of PTC using a PTC cell line. Methods: CCK-8 assay, colony formation assay and EdU assay were used to detect the cell viability. Flow Cytometry was used to detect the cell cycle and apoptosis. Transwell and scratch assay were used to detect the cell motility. Results: CCK-8 assay, colony formation assay and EdU assay revealed that lncRNAs (ENST00000537266 and ENST00000426615) could inhibit cell proliferation. Cell cycle analysis showed that cell proportion was statistically significant increased in G1 phase and decreased in S phase and G2 phase in Si-266 transfected TPC-1 cells. In addition, a noteworthy increase of cell proportion in G1 phase accompanied by a decrease in S phase and unchanged G2 phase in Si-615 transfected TPC-1 cells were also observed. Meanwhile, transwell and scratch assay showed that ENST00000426615 could inhibit the cell motility while ENST00000537266 could not. Conclusion: Our results showed that lncRNAs (ENST00000426615 and ENST00000537266) might be important regulators of PTC cell proliferation and motility, which might provide new insight into the understanding of PTC pathogenesis.


1987 ◽  
Vol 7 (1) ◽  
pp. 444-449 ◽  
Author(s):  
J P Durkin ◽  
J F Whitfield

NRK cells infected with a temperature-sensitive Kirsten sarcoma virus (ts371 KSV) are transformed at 36 degrees C, but are untransformed at 41 degrees C which inactivates the abnormally thermolabile oncogenic p21Ki product of the viral Ki-ras gene. At 41 degrees C, tsKSV-infected NRK cells were arrested in G0/G1 when incubated in serum-free medium, but could then be stimulated to transit G1, replicate DNA, and divide by adding serum at 41 degrees C or dropping the temperature to a p21-activating 36 degrees C without adding serum. When quiescent cells at 41 degrees C were stimulated to transit G1 in serum-free medium by activating p21 at 36 degrees C and then shifted back to the p21-inactivating 41 degrees C in the mid-S phase, they continued replicating DNA but could not transit G2. Reactivating p21 in the G2-arrested cells by once again lowering the temperature to 36 degrees C stimulated a rapid entry into mitosis. By contrast, while serum-stimulated quiescent G0 cells at 41 degrees C replicate DNA and divide, serum did not induce G2-arrested cells to enter mitosis, indicating that serum growth factors may trigger events in the G1 phase that ultimately determine G2 transit. These observations made with the viral ras product suggest that cellular ras proto-oncogene products have a role in G2 transit of normal cells.


Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 471-486 ◽  
Author(s):  
Debbie T Liang ◽  
Susan L Forsburg

Abstract MCM proteins are required for the proper regulation of DNA replication. We cloned fission yeast mcm7+ and showed it is essential for viability; spores lacking mcm7+ begin S phase later than wild-type cells and arrest with an apparent 2C DNA content. We isolated a novel temperature-sensitive allele, mcm7-98, and also characterized two temperature-sensitive alleles of the fission yeast homolog of MCM10, cdc23+. mcm7-98 and both cdc23ts alleles arrest with damaged chromosomes and an S phase delay. We find that mcm7-98 is synthetically lethal with the other mcmts mutants but does not interact genetically with either cdc23ts allele. However, cdc23-M36 interacts with mcm4ts. Unlike other mcm mutants or cdc23, mcm7-98 is synthetically lethal with checkpoint mutants Δcds1, Δchk1, or Δrad3, suggesting chromosomal defects even at permissive temperature. Mcm7p is a nuclear protein throughout the cell cycle, and its localization is dependent on the other MCM proteins. Our data suggest that the Mcm3p-Mcm5p dimer interacts with the Mcm4p-Mcm6p-Mcm7p core complex through Mcm7p.


Cell ◽  
1990 ◽  
Vol 63 (2) ◽  
pp. 313-324 ◽  
Author(s):  
John P.H. Th'ng ◽  
Paul S. Wright ◽  
Joyce Hamaguchl ◽  
Melanie G. Lee ◽  
Chrlstopher J. Norbury ◽  
...  

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1221-1233 ◽  
Author(s):  
Kathleen L Gould ◽  
C Geoffrey Burns ◽  
Anna Feoktistova ◽  
Ching-Pei Hu ◽  
Sally G Pasion ◽  
...  

Abstract A mutation within the Schizosaccharomyces pombe cdc24+ gene was identified previously in a screen for cell division cycle mutants and the cdc24+ gene was determined to be essential for S phase in this yeast. We have isolated the cdc24+ gene by complementation of a new temperature-sensitive allele of the gene, cdc24-G1. The DNA sequence predicts the presence of an open reading frame punctuated by six introns which encodes a pioneer protein of 58 kD. A cdc24 null mutant was generated by homologous recombination. Haploid cells lacking cdc24+ are inviable, indicating that cdc24+ is an essential gene. The transcript of cdc24+ is present at constant levels throughout the cell cycle. Cells lacking cdc24+ function show a checkpoint-dependent arrest with a 2N DNA content, indicating a block late in S phase. Arrest is accompanied by a rapid loss of viability and chromosome breakage. An S. pombe homolog of the replicative DNA helicase DNA2 of S. cerevisiae suppresses cdc24. These results suggest that Cdc24p plays a role in the progression of normal DNA replication and is required to maintain genomic integrity.


Development ◽  
1992 ◽  
Vol 116 (3) ◽  
pp. 745-754 ◽  
Author(s):  
H. Skaer ◽  
A. Martinez Arias

Cell division in the Malpighian tubules of Drosophila melanogaster depends on the presence of a specialised cell at the tip of each tubule (Skaer, H. le B (1989) Nature 342, 566–569). Here we show that cell division also depends on the normal expression of the segment polarity gene, wingless. The pattern of wingless RNA and protein in developing tubules is consistent with a requirement for wingless for cell division. Analysis of the temporal requirement for wingless using a temperature- sensitive allele confirms that the normal expression of wingless is necessary during cell proliferation in the Malpighian tubules. Over-expression of the gene, induced in a stock containing the wg gene under the control of a heat-shock promoter, results in supernumerary cells in the tubules. We discuss the role of wingless in the cell interactions that govern cell division in the Malpighian tubules.


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