RESUMO
Long-term cultivation of human cells, including stem cells, can lead to substantial transformation of the karyotype and occurrence of genetic instability. The aim of this research was a comparative cytogenetic study of the karyotype of a new human stem cell line 4BL at 160 and 205 passages. The absence of 10 and 13 pairs of chromosomes and the monosomy of chromosomes 4, 8, 10, 11, 13, 15, 17, 21, X were observed; also six regular marker chromosomes were detected. Chromosomes 1, 15 and 21 are involved in translocations t(l;11), t(5;15), t(12; 15), t(16;21). Modal class of the karyotype is within 41-43 chromosomes at both 160 and 205 passages. The frequency of polyploid cells have been increased from 2.8% at 160 passage up to 36% at 205 passage. Cells with a near-haploid karyotype were not detected at 205 passage (in contrast to 24.6% at 160 passages) and a decline of the level of premature separation of chromatids was observed. We assume stabilization of karyotype of the cell line 4BL at 205 passage and consider that further research is needed to predict the direction of karyotypic evolution of these cells in vitro.
Assuntos
Efeito Fundador , Cariótipo , Ploidias , Células-Tronco/metabolismo , Translocação Genética , Linhagem Celular , Transformação Celular Neoplásica , Deleção Cromossômica , Cromossomos Humanos Par 10 , Cromossomos Humanos Par 13 , Marcadores Genéticos , Humanos , Cariotipagem , Monossomia , Células-Tronco/patologiaRESUMO
Using in silico analysis a number of potential sites for post-translational modifications has been revealed within the human O6-methylguanine-DNA methyltransferase (MGMT) protein. In particular these were the acetylation of Gly3 residue in the N-terminus of protein and internal residues Lys132 and Lys135; Arg166 residue methylation; Lys63 SUMOylation and ubiquitination of Lys31, Lys39, Lys49, Lys63, Lys67, Lys135, Lys156, Lys196, Lys209. Also it has been predicted 16 novel potential phosphorylation sites of serine residues (positions 13, 124, 144, 182, 183, 190, 215, 216 and 230), tyrosine residues (positions 100 and 189) and threonine residues (positions 23, 69, 94, 126 and 229), as well as five binding sites for kinases and other proteins (Serl3 with 14-3-3, Val21 and Ile172 with D-domain, Pro78 and Pro111 with SH3-domain, Pro111 with MAPK3). Some kinases predicted by the authors are known as partners of the MGMT protein, that confirms the probability of modification of the given sites. Potential sites require further experimental confirmation of modifications and investigation of their influence on stability and DNA-repair activity of this protein.
Assuntos
Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Proteínas Quinases/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas Supressoras de Tumor/metabolismo , Acetilação , Sequência de Aminoácidos , Sítios de Ligação , Biologia Computacional , Metilases de Modificação do DNA/química , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/química , Enzimas Reparadoras do DNA/genética , Humanos , Metilação , Dados de Sequência Molecular , Fosforilação , Ligação Proteica , Estrutura Terciária de Proteína , Sumoilação , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/genética , UbiquitinaçãoRESUMO
Data concerning human mobile genetic elements which make up 45% of the genome are reviewed. Much attention is focused on their role in genome functioning, such as recombination, regulation of gene expression and neogenes besides classification and distribution.
Assuntos
Genoma Humano , Sequências Repetitivas Dispersas/genética , Elementos Alu , Animais , Cromossomos Humanos , Evolução Molecular , Regulação da Expressão Gênica , Humanos , Recombinação GenéticaRESUMO
Growth and morphological properties of a novel mouse cell line G1 have been investigated. It has been shown that cells of this cell line possess the ability of spontaneous transformation in vitro: the cells have unlimited growth in culture, grow in medium with a low serum content and form multilayer colonies on a cell monolayer and cell colonies inside agar. Using micronucleus test it has been revealed that cells of the G1 cell line possess different forms of aberrant mitosis. The results indicate the neoplastic G1 cell transformation with aberrant mitosis.
