RESUMO
We report the first identified mutation in the gene encoding human cytochrome c (CYCS). Glycine 41, invariant throughout eukaryotes, is substituted by serine in a family with autosomal dominant thrombocytopenia caused by dysregulated platelet formation. The mutation yields a cytochrome c variant with enhanced apoptotic activity in vitro. Notably, the family has no other phenotypic indication of abnormal apoptosis, implying that cytochrome c activity is not a critical regulator of most physiological apoptosis.
Assuntos
Apoptose/fisiologia , Citocromos c/genética , Mutação/genética , Transdução de Sinais , Trombocitopenia/etiologia , Fator Apoptótico 1 Ativador de Proteases/metabolismo , Feminino , Ligação Genética , Humanos , Masculino , Megacariócitos/metabolismo , Megacariócitos/patologia , Oxirredução , Linhagem , Contagem de Plaquetas , Serina/química , Serina/genética , Trombocitopenia/patologiaRESUMO
Two novel families of miniature inverted repeat transposable elements (MITEs), Vege and Mar, are described from Drosophila willistoni. Based on their structures, both element families are hypothesized to belong to the hAT superfamily of transposable elements. Both elements have perfect, inverted terminal repeats and 8-bp target site duplications and were found to have inserted within fixed copies of nonautonomous P elements. Vege is present in all studied D. willistoni populations and appears to have a relatively low copy number. Mar was identified in only a single D. willistoni population, and its copy number is presently unknown. Although MITEs occupy relatively large proportions of the genomes of a broad range of organisms, this may be their first unambiguous identification in any species of the genus Drosophila.
