BACKGROUND: Mutations in centrosomal protein genes have been identified in a number of genetic diseases in brain development, including microcephaly. Centrosomal P4.1-associated protein (CPAP) is one of the causal genes implicated in primary microcephaly. We previously proposed that CPAP is essential for mother centriole maturation during mitosis. METHODS: We immunostained CPAP-depleted cells using the ninein antibody, which selectively detects subdistal appendages in mature mother centrioles. RESULTS: Ninein signals were significantly impaired in CPAP-depleted cells. CONCLUSION: The results suggest that CPAP is required for mother centriole maturation in mammalian cells. The selective absence of centriolar appendages in young mother centrioles may be responsible for asymmetric spindle pole formation in CPAP-depleted cells.
Brain ; Cell Cycle ; Centrioles* ; Centrosome ; Humans ; Microcephaly ; Mitosis ; Mothers* ; Spindle Poles

To identify the component(s) involved in cell cycle control in the protozoan Giardia lamblia, cells arrested at the G1/S- or G2-phase by treatment with nocodazole and aphidicolin were prepared from the synchronized cell cultures. RNA-sequencing analysis of the 2 stages of Giardia cell cycle identified several cell cycle genes that were up-regulated at the G2-phase. Transcriptome analysis of cells in 2 distinct cell cycle stages of G. lamblia confirmed previously reported components of cell cycle (PcnA, cyclin B, and CDK) and identified additional cell cycle components (NEKs, Mad2, spindle pole protein, and CDC14A). This result indicates that the cell cycle machinery operates in this protozoan, one of the earliest diverging eukaryotic lineages.
Aphidicolin ; Cell Culture Techniques ; Cell Cycle ; Cell Cycle Checkpoints ; Cyclin B ; Gene Expression Profiling ; Genes, cdc ; Giardia lamblia ; Giardia ; Nocodazole ; Spindle Poles

Previously, we have reported that CKAP2 is involved in the maintenance of centrosome integrity, thus allowing for proper mitosis in primary hepatocytes. To understand this biological process, we identified the mitosis-specific phosphorylation sites in mouse CKAP2 and investigated CKAP’s possible role in cell cycle progression. Because we observed mouse CKAP2 depletion in amplified centrosomes and aberrant chromosomal segregation, which was rescued by ectopic expression of wild-type CKAP2, we focused on the centrosome duplication process among the various aspects of the cell cycle. Among the identified phosphorylation sites, T603 and possibly S608 were phosphorylated by CDK1–cyclin B1 during mitosis, and the ectopic expression of both T603A and S608A mutants was unable to restore the centrosomal abnormalities in CKAP2-depleted cells. These results indicated that the phosphorylation status of CKAP2 during mitosis is critical for controlling both centrosome biogenesis and bipolar spindle formation.
Animals ; Biological Processes ; Cell Cycle ; Centrosome* ; Ectopic Gene Expression ; Hepatocytes ; Mice ; Mitosis ; Phosphorylation*

In humans and most mammals, the sperm centrosome is primarily responsible for nucleating and organizing the sperm astar, which pushes the sperm head toward the oocyte center and guides the migration of the female pronucleus, completing the fertilization process. There are about 200 kinds of protein in the human sperm centrosome. Currently, most of the researches focus on the centrin protein. Further studies on the functions of different human sperm centrosomal proteins may contribute to the understanding of the causes of the failures in assisted reproductive technology (ART). And in ART, morphological observation of the sperm neck integrity is the only way for primary evaluation of the function of the sperm centrosome.
Calcium-Binding Proteins ; physiology ; Centrosome ; physiology ; Chromosomal Proteins, Non-Histone ; physiology ; Humans ; Male ; Reproductive Techniques, Assisted ; Spermatozoa ; cytology

OBJECTIVEIt is currently considered that the defect of mitotic spindle caused by centrosome abnormalities may be one of the reasons for the development of aneuploidy in tumors. This study attempted to elucidate the possible role of centrosome defects in the development and progression of OSCC by investigating the frequency of centrosome amplification in oral precancerous lesions and OSCC.

METHODSFormalin-fixed, paraffin-embedded tissues of 12 cases of normal oral epithelium, 22 case of dysplasia with different degree epithelium dysplasia and 32 cases of OSCC with different differentiation were investigated for centrosome status by using indirect immunofluorescence double staining with antibodies to centrosome protein gamma-tubulin and cytokeratin. The differences and the change trend of centrosome status in these groups were statistically analyzed by SPSS10.0.

RESULTSNormal oral epithelium showed normal centrosomes in epithelium cells, while 16 of 22 cases (72.73%) of dysplasia (DYS) and 27 of 32 cases (84.38%) of OSCC showed the evidence of centrosome amplification and morphological abnormalities characterized by huge size, clump or supernumerary centrosomes in a fraction of epithelium or tumor cells. The percentage of cells with abnormal centrosomes increased gradually from mild-dysplasia epithelium to poorly differentiated OSCC, which positively correlated with the histologicalcytologic grade of oral precancerous lesions and OSCC (P < 0.01).

CONCLUSIONCentrosome amplification was an early event and that might play a role in the establishment and perhaps the progression of OSCC. There might be some direct relationship between centrosome defects and the cellular morphological phenotype characteristics of dysplasia and OSCC. Centrosome amplification could be served as an alternative diagnostic indicator of dysplasia and the intervention of centrosome cycle might serve as a particular way for the prevention and treatment of OSCC in the future.

Carcinoma, Squamous Cell ; genetics ; pathology ; Centrosome ; pathology ; Humans ; Mouth Mucosa ; pathology ; Mouth Neoplasms ; genetics ; pathology ; Precancerous Conditions ; pathology

OBJECTIVETo investigate the relationship between centrosome abnormalities and aneuploidy in oral squamous cell carcinoma (OSCC) and elucidate the possible underlying mechanisms of chromosome instability (CIN) in OSCC.

METHODSFormalin-fixed, paraffin-embedded tissues of 8 cases of normal oral epithelium and 32 cases of OSCC were examined for centrosome status by using indirect immunofluorescence staining, and chromosome instability (aneuploidy) in some tissues were detected by flow cytometry. The correlation between centrosome abnormalities and aneuploidy in OSCC was statistically analyzed by SPSS12.0.

RESULTSNormal oral epithelium showed normal size and number of centrosomes in epithelium cells, while 25 out of 32 cases of OSCC showed the evident centrosome amplification characterized by huge size and/or supernumerary centrosomes in a fraction of tumor cells, and 21 out of 32 cases were aneuploidy. The percentage of cases with abnormal centrosomes in aneuploid OSCC (19/21) was significantly higher than that in diploid OSCC(6/11) (P =0.032). Centrosome abnormality was significantly correlated with aneuploidy (Spearman r = 0.413, P = 0.047), and a positive correlation was found between the degree of centrosome amplification and the degree of DNA ploidy abnormality (Pearson r = 0.364, P = 0.041).

CONCLUSIONSCentrosome abnormality may be a contributing factor for chromosome instability in OSCC.

Aneuploidy ; Carcinoma, Squamous Cell ; genetics ; pathology ; Centrosome ; pathology ; Chromosomal Instability ; Humans ; Mouth Mucosa ; pathology ; Mouth Neoplasms ; genetics ; pathology

OBJECTIVETo observe the effect of recombinant adenovirus-mediated wild-type p53 gene on the number and proteins of centrosome in K562 cells. To explore the possibility of application of wild-type p53 gene therapy in the treatment of chronic myeloid leukemia.

METHODSThe recombinant adenoviruses carrying wild-type p53 gene (Ad5 wtp53), mutant p53 gene (Ad5 mtp53) or the green fluorescent protein (GFP) gene was repeatedly amplified and co-infected into K562 cells with cation polybrene. The optimal infection titer and infection time of the recombinant adenoviruses were determined by MTT assay, p53 mRNA and protein expression were determined by RT-PCR and Western blot respectively. The centrosomal structural protein gamma-tubulin and the spindle protein alpha-tubulin were marked simultaneously by indirect immunofluorescence staining, and the expression of the centrosomal gamma-tubulin protein, the mitosis and the number of centrosome were observed under the laser confocal microscopy.

RESULTSInfection efficiency with recombinant adenoviruses was facilitated by polybrene in K562 cells, and 4 microg/ml polybrene was chosen. The optimal adenovirus infection titer was 20,000 MOI and the optimal infection time was 72 hours. p53 mRNA and P53 protein can be expressed in K562 cells by Ad5wtp53 and Ad5mtp53. Both the expression of the centrosomal gamma-tubulin protein and the number of centrosomes were decreased after Ad5wtp53 infection.

CONCLUSIONThere is sustained expression of P53 protein in K562 cells after its infection by Ad5wtp53. Wild-type P53 protein can lead to the down-regulation of the number of centrosomes and the expression of centrosomal gamma-tubulin protein in K562 cells.

Adenoviridae ; genetics ; Centrosome ; metabolism ; Genes, p53 ; genetics ; Genetic Vectors ; Humans ; K562 Cells ; Transfection ; Tubulin ; metabolism ; Tumor Suppressor Protein p53 ; metabolism

OBJECTIVETo analyze the centrosome abnormalities in the malignant transformation of human bronchial epithelial cells (BEAS-2B) induced by coal tar pitch smoke extracts and to investigate the role and action mechanism of centrosome in the lung cancer induced by coal tar pitch.

METHODSMedium-temperature coal tar pitch smoke extracts were used to treat immortalized human bronchial epithelial cells (BEAS-2B) and establish a malignant transformation model. The treated BEAS-2B cells were used as exposure group, and solvent control group and normal control group were also set for passage culture. The changes of centrosome in BEAS-2B cells seeded on coverslips were evaluated by indirect immunofluorescence assay. The mRNA expression of p53, p21, and cyclin E in BEAS-2B cells was measured by real-time quantitative RT-PCR, and their protein levels in BEAS-2B cells seeded on coverslips were measured by semiquantitative immunohistochemical analysis.

RESULTSThe overall rate of centrosome abnormalities in BEAS-2B cells at passage 20 was 6.56±1.01% in the exposure group, significantly higher than those in the normal control group (3.40±0.86%) and solvent control group (3.14±0.59%) (P < 0.05). In addition, the exposure group had a significantly higher overall rate of centrosome abnormalities in BEAS-2B cells at passage 30 compared with the normal control group and solvent control group (22.39±9.5% vs 4.34±1.04%, P < 0.05; 22.39±9.5% vs 4.33±1.20%, P < 0.05). Compared with the normal control group and solvent control group, the exposure group had significantly decreased mRNA and protein expression of p53 and significantly increased mRNA and protein expression of cyclin E in BEAS-2B cells at passages 20 and 30 (P < 0.05).

CONCLUSIONCentrosome abnormalities occur before the malignant transformation in BEAS-2B cells treated with coal tar pitch smoke extracts, and they may be mediated by the p53/p21/cyclin E signaling pathway.

Cell Line ; Cell Transformation, Neoplastic ; metabolism ; pathology ; Centrosome ; metabolism ; pathology ; Coal Tar ; Cyclin E ; metabolism ; Epithelial Cells ; cytology ; metabolism ; Humans ; Signal Transduction ; Smoke ; Tumor Suppressor Protein p53 ; metabolism

Centrosomes maintain genomic stability by establishing the bipolar spindles during cell division and, execute accurate segregation of chromosomes during mitosis. In this study, we have demonstrated that there are three forms of STK-15 gene in breast cancer cell lines. Alternative splice positions are located in 5'-untranslated region of STK15 gene. The results of in vitro translation experiments revealed that the alternative splicing in the 5'-untranslated region of STK15 had no effect on protein translation. The differential expression patterns of these alternatively spliced STK15 in breast cell lines and primary tumors therefore suggest that STK15 gene transcription may be differentially regulated or stabilized in these cells.
*5' Untranslated Regions ; *Alternative Splicing ; Base Sequence ; Breast Neoplasms/enzymology/*genetics ; Centrosome/*enzymology ; Female ; Human ; Molecular Sequence Data ; Protein-Serine-Threonine Kinases/*genetics ; Tumor Cells, Cultured

BACKGROUND: Aneuploidy has been suggested as one of the major causes of cancer from the time of Boveri. In support of this notion, many studies have shown that cancer cells exhibit aneuploidy. However, there are evidences that do not support the aneuploidy hypothesis. We have previously reported that the spindle assembly checkpoint protein BubR1 is acetylated in mitosis and that the acetylation of BubR1 is crucial for checkpoint maintenance and chromosome-spindle attachment. Mice heterozygous for acetylation-deficient BubR1 (K243R/+) spontaneously develop cancer with chromosome instability. As K243R/+ mice develop hepatocellular carcinoma, we set out to test if chromosome mis-segregation was the cause of their liver cancer. METHODS: Primary hepatocytes in the regenerating liver after partial hepatectomy (PH) were analyzed and compared for various mitotic parameters. RESULTS: Primary hepatocytes isolated from K243R/+ mice after PH displayed a marked increase of chromosome misalignment, accompanied by an increase of micronuclei. In comparison, the number of nuclei per cell and the centrosome numbers were not different between wild-type and K243R/+ mice. Taken together, chromosome mis-segregation provokes tumorigenesis in mouse liver. CONCLUSION: Our results corroborate that PH provides a reliable tool for assessing mitotic infidelity and cancer in mice.
Acetylation ; Aneuploidy ; Animals ; Carcinogenesis* ; Carcinoma, Hepatocellular ; Centrosome ; Chromosomal Instability ; Hepatectomy* ; Hepatocytes ; Hydrogen-Ion Concentration ; Liver ; Liver Neoplasms ; M Phase Cell Cycle Checkpoints ; Mice* ; Mitosis