Study On The Dynamic Distribution Of Histone Phosphorylation In The Mitosis Of Sf9 Cell

The chromosome consists of DNA and histone,and the core histone includes H2 A,H2B,H3 and H4.The N-terminal amino acid residues of these four core histones can undergo a series of post-translational modifications to participate in different biological functions,including phosphorylation,ubiquitination,methylation,acetylation and sumo.These modifications can change the basic charge properties of the amino acid terminal of histone,thus affecting the interaction between histone,DNA and non histone.Chromatin condensation and subsequent decentralization are necessary for the correct execution of various cellular events.In mitosis,chromatin condensation is the most complex,and chromatin relaxation is necessary for DNA replication,repair,recombination and gene transcription.Mitosis is the main mode of cell proliferation in animals and plants.The chromosome also changes dynamically with the mitotic cycle: from the highly disordered chromatin filament state in the interphase to the highly condensed chromosome state in the metaphase,which can be seen clearly under the microscope,and then to the state of chromatin filament in the anaphase when the chromosome is depolymerized.Many genes participate in the regulation of chromatin condensation in this process.There are many phosphorylation sites at h3 n end of histone,such as Thr3,Ser10,Thr11 and Ser28.Interestingly,H3 phosphorylation at Ser10,Thr11 and Ser28 sites has been observed in the genomic region of the transcriptional active gene.Therefore,H3 phosphorylation is involved in the process that requires the opposite chromatin state.Studies in mammalian cell mitosis have shown that the phosphorylation of histone H3 Ser10 starts in the heterochromatin region near the centromere at the late G2 stage,then extends to the whole condensed chromosome,and ends before the prophase.In addition,the phosphorylation of histone H3 Thr3 in Sf9 cells occurred in the specific position of the cell chromosome in the early stage.With the progress of cell cycle,the phosphorylation signal gradually increased,reaching the highest level in the middle stage.At the later stage of mitosis,the distribution of histone H3 Thr3 in the equatorial plate of daughter cells was uniform,and at the end ofmitosis,only a weak phosphorylation signal remained in the equatorial plate.After that,the relationship between histone H3 Ser10 phosphorylation and chromatin condensation has been confirmed in many species,and the dynamic changes of chromosome condensation have also occurred in meiosis.Interestingly,it has been reported that histone H3 Thr3 phosphorylation can correctly regulate the correct separation of chromosomes during mitosis.In addition,it has been shown that histone H3 Ser10 and H3 Thr3 phosphorylation may also participate in the division of cytoplasm and play an important role in the formation of mesosomes.In this study,specific anti histone H3 Ser10 and H3 Thr3 phosphorylation antibodies were used to detect the dynamic distribution of H3 Ser10 and Thr3 phosphorylation during mitosis of Spodoptera ferrugiperda Sf9 cell line by immunofluorescence technology,providing basic information for the function of H3 Ser10 and H3 Thr3 phosphorylation in insect Sf9 cell mitosis The main results are as follows:1.The first 60 amino acids of histone H3 were highly conserved in most species.2.The antibody was prepared by the synthesis of peptide(TGGKAPRKQLC)and(KQTARKC)containing phosphorylation modification site.3.Histone H3 Ser10 phosphorylation occurred near the nuclear membrane of the cells in the early prophase and distributed in dots.With the development of cell cycle,it reached the highest level in the early metaphase and concentrated on the whole chromosome.Dephosphorylation began at the later stage of mitosis and completed at the later stage.It is suggested that the phosphorylation of histone H3 Ser10 is related to the condensation of chromatin in the mitosis of Sf9 cells.4.The phosphorylation of histone H3 Thr3 in Sf9 cells occurred in the specific position of the chromosome in the prophase,reached the highest level in the metaphase,and only a weak phosphorylation signal remained in the specific position of the equatorial plate in the anaphase.These results indicate that the phosphorylation of histone H3 Thr3 is related to the condensation of chromatin and cytokinesis in Sf9 cell mitosis.