RESUMEN
Geminin is a multifunctional protein which localizes in nucleus,it has complicated structural and functional domains.Geminin plays very important roles in cell proliferation,embryonic development,tumorigenesis and so on.Geminin affects cell proliferation through influence on the important events in cell cycle phases.There are many mechanisms by which Geminin can control DNA replication,inhibit centrosome over-duplication,promote G2/M phase progression,maintain proper cytokinesis.At different development stages,Geminin acts as an inhibitor or inducer in regulating embryonic development,especially in nervous system formation.Geminin also plays a regulative role in eye development and embryonic development through the interactions with homeobox genes or proteins Six3 and Hox,Geminin functions as a coordinator of cell proliferative and differentiative control.Recently,Geminin was found to have relationship with cancer,the study on the function of Geminin in cancer has been a meaningful aspect.Geminin can act as a marker to evaluate progression and prognosis in cancer.It may be a novel molecular target in therapy of cancer.The activity of Geminin is regulated by transcription level and post-transcription level,the post-transcriptional regulation of Geminin protein may take the main position.
RESUMEN
The synchronized HeLa cells were used to study the effect of protein kinase A(PKA) inhibitor on the progression of S phase. Synchronized cell s in S phase were obtained by the method of TdR double block through 3H-T dR incorporation assay. The PKA inhibitor typeⅢ obviously increased the level of 3H-TdR incorporation of S phase in HeLa cells. In contrast with contro l, the activity of thymidine kinase (TK) in S phase increased, too. It indicated that PKA played an inhibitory role in S phase progression of HeLa cells. With t he method of Western blotting, the PKA inhibitor typeⅢ enhanced the level of C yclinA and PCNA, inhibited the expression of p21, which is a negative regulator of cell cycle, but had no effect on the expression of CDK2. The results showed t hat PKA could negatively regulate the S phase progression by affecting the level of CyclinA, PCNA and influencing the expression of p21 protein. This may be one of the molecular mechanisms which is involved in the negative regulation of S p hase progression by PKA in HeLa cells.
RESUMEN
The plasmid pXJ-41-p15, which contains the full length DNA coding for p15 was introduced into human melanoma cell line A375 in which p 15 was deleted by DNA recombination and transfection. Using G418, the positive clones were selected. And the cell model overexpressing p15 was constructed suc cessfully through the analysis of PCR and Western blot. It is showed tha t the expression of p15 was further enhanced after the cells overexpressing p15 were treated with PMA for 72 hours. In contrast of the control cells, the PKC a ctivity was further declined in the cells overexpressing p15 after treated with PMA. At the same time, the growth rate of cell was decreased more significantly and approximate 30% apoptotic cells were found. The expression of Caspase-3(P2 0) was increased in the apoptotic cells. It is indicated that CKI p15 was relat ed to PKC signal transduction in the regulation of cell proliferation and apopto sis. They may be involved in the apoptotic pathway including Caspase3, thus indu cing the apoptosis of cells.
RESUMEN
Objective To investigate the correlation between phosphatidylinositol 3 kinase (PI3-kinase) and the pathogenesis of psoriasis. Methods By dot hybridization, in situ hybridization and immunohistochemistry, expression of PI3 kinase was observed in twelve psoriatic and five normal epidermis. Results In psoriatic epidermis, expression of PI3 kinase gene and protein was elevated obviously compared with that of normal skin. Conclusion PI3 kinase may be closely associated with hyperproliferation of psoriatic keratinocytes.