RESUMO
System X(c)(-) is an anionic amino acid transport system highly specific for cystine and glutamate. The underlying mechanism of cell death of cultured cells from the subtle gray (sut) mouse which contains an xCT null mutation remains elucidated. Our results show that the death of sut cells is likely caused by apoptosis mediated by c-Jun N-terminal kinase (JNK). The JNK activation triggers both a caspase-dependent (caspases-9 and -3) and an ER stress-mediated (eIF2 and CHOP) pathway to induce apoptosis. These findings suggest the possible pathways involved in the cell death of xCT-deficient cells.
Assuntos
Sistema y+ de Transporte de Aminoácidos/genética , Apoptose/genética , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Melanócitos/fisiologia , Animais , Caspase 3/metabolismo , Caspase 9/metabolismo , Linhagem Celular , Retículo Endoplasmático/metabolismo , Fator de Iniciação 2 em Eucariotos/metabolismo , Melanócitos/metabolismo , Camundongos , Camundongos Mutantes , Fator de Transcrição CHOP/metabolismoRESUMO
The allele frequency of four allozyme loci in four grasshopper species from two families of Catantopidae and Oedipodidae was examined using horizontal starch gel electrophoresis. The zymograms show that all four species have two loci in malate dehydrogenase (MDH). At MDH-1 one moderately migrated allele is shared and dominant in all four species. Locusta migratoria manilensi has two allele fixations in lactate dehydrogenase (LDH) and malic enzyme (ME); while Gastrimargus saussure has a fixed allele at MDH-1 and a unique fixation at MDH-2. The overall genetic variance was the highest in Oxya chinensis (Allele per locus = 3.0; He = 0.22), but the lowest in L. migratoria manilens (Allele per locus = 1.5; He = 0.013). Allozyme data suggests the four species are close in phylogenetic relationship, but differentiated in genetic variation levels.