RESUMO
Metallothioneins (MTs) are ubiquitous metal-binding, cysteine-rich proteins, associated with metal accumulation and thus providing protection against toxic heavy metals such as cadmium (Cd). To investigate the mechanisms of enrichment of Cd in the earthworm Pheretima aspergillum, we isolated and cloned metallothionein-2 (MT-2) cDNA (538 bp) from P. aspergillum, analyzed its sequence, and examined MT-2 transcription levels by relative quantitative real-time PCR under different concentrations of Cd. The sequence of P. aspergillum MT-2 cDNA and its putative amino acid sequence were highly similar to sequences from other earthworms. The induction with Cd increased the MT-2 gene transcription level in a dose-dependent manner. In addition, earthworm recombinant MT-2 exhibited high Cd bioaccumulation ability in vitro. These results suggested that MT-2 plays an important role in tolerance and accumulation of Cd in P. aspergillum.
Assuntos
Clonagem Molecular , Expressão Gênica , Metalotioneína/genética , Oligoquetos/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Cloreto de Cádmio/farmacologia , DNA Complementar/química , DNA Complementar/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Metais Pesados/metabolismo , Dados de Sequência Molecular , Oligoquetos/classificação , Filogenia , Proteínas Recombinantes de Fusão , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
Drought is a major limiting factor in crop production. Rewatering is a process opposite to drought, allowing plants to recover to their normal physiological state. To understand more thoroughly the set of genes involved in plant response to drought, we comparatively and jointly analyzed the microarray data of drought and rewatering experiments in Arabidopsis. A total of 3833 differentially expressed genes (DEGs) were identified. Among them, ~74% were proven to be co-regulated by drought and rewatering. Drought and rewatering showed contrary regulatory effects on almost all of these co-regulated genes. Only ~6% of the DEGs were significantly regulated by drought alone, and the remaining ~20% were significantly regulated by rewatering alone. However, gene ontology analysis suggested that those "rewatering-only" genes also appeared to be related, either directly or indirectly, to drought response.