Huntington＇s disease （HD） is caused by abnormal CAG repeat expansion in the 5＇-end of the Huntingtin （HTT） gene. In addition to the canonical C-terminal full-length huntingtin （htt） nuclear export signal, a cy...Huntington＇s disease （HD） is caused by abnormal CAG repeat expansion in the 5＇-end of the Huntingtin （HTT） gene. In addition to the canonical C-terminal full-length huntingtin （htt） nuclear export signal, a cytoplasmic localization-related domain （CLRD） in the N-terminus of htt has recently been reported. Here, we analyzed this domain by introducing deletion and substitution mutations in a truncated N-terminal htt protein and subsequently monitored htt expression, aggregation and subcellular localization by immunocytochemistry and Western blot analysis. We demonstrated that Htt1-17 was the essential sequence for htt cytoplasmic localization. We also found that the subcellular distribution of htt was altered when Htt1_17 was mutated to contain amino acids of different charges, suggesting a structural requirement of Htt1-17 for the cytoplasmic localization of htt. Deletion of the first three amino acids did not affect its association with mitochondria. We observed that defective cytoplasmic localization resulted in a reduction of total htt aggregates and increased nuclear aggregates, indicating that the subcellular distribution of the protein might influence the aggregation process. These studies provide new insight into the molecular mechanism of htt aggregation in HD.展开更多
Synaptosomal-associated protein 25 k Da（SNAP-25） is localized on the synapse and participates in exocytosis and neurotransmitter release. Decreased expression of SNAP-25 is associated with Alzheimer＇s disease and a...Synaptosomal-associated protein 25 k Da（SNAP-25） is localized on the synapse and participates in exocytosis and neurotransmitter release. Decreased expression of SNAP-25 is associated with Alzheimer＇s disease and attention deficit/hyperactivity disorder. However, the expression of SNAP-25 in spinal cord contusion injury is still unclear. We hypothesized that SNAP-25 is associated with sensory and locomotor functions after spinal cord injury. We established rat models of spinal cord contusion injury to detect gene changes with a gene array. A decreased level of SNAP-25 was detected by quantitative real time-polymerase chain reaction and western blot assay at 1, 3, 7, 14 and 28 days post injury. SNAP-25 was localized in the cytoplasm of neurons of the anterior and posterior horns, which are involved in locomotor and sensory functions. Our data suggest that reduced levels of SNAP-25 are associated with sensory and locomotor functions in rats with spinal cord contusion injury.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.30770761 and 30971000)
文摘Huntington＇s disease （HD） is caused by abnormal CAG repeat expansion in the 5＇-end of the Huntingtin （HTT） gene. In addition to the canonical C-terminal full-length huntingtin （htt） nuclear export signal, a cytoplasmic localization-related domain （CLRD） in the N-terminus of htt has recently been reported. Here, we analyzed this domain by introducing deletion and substitution mutations in a truncated N-terminal htt protein and subsequently monitored htt expression, aggregation and subcellular localization by immunocytochemistry and Western blot analysis. We demonstrated that Htt1-17 was the essential sequence for htt cytoplasmic localization. We also found that the subcellular distribution of htt was altered when Htt1_17 was mutated to contain amino acids of different charges, suggesting a structural requirement of Htt1-17 for the cytoplasmic localization of htt. Deletion of the first three amino acids did not affect its association with mitochondria. We observed that defective cytoplasmic localization resulted in a reduction of total htt aggregates and increased nuclear aggregates, indicating that the subcellular distribution of the protein might influence the aggregation process. These studies provide new insight into the molecular mechanism of htt aggregation in HD.
基金supported by the National Undergraduate Innovation Training Project of China,No.201313705005
文摘Synaptosomal-associated protein 25 k Da（SNAP-25） is localized on the synapse and participates in exocytosis and neurotransmitter release. Decreased expression of SNAP-25 is associated with Alzheimer＇s disease and attention deficit/hyperactivity disorder. However, the expression of SNAP-25 in spinal cord contusion injury is still unclear. We hypothesized that SNAP-25 is associated with sensory and locomotor functions after spinal cord injury. We established rat models of spinal cord contusion injury to detect gene changes with a gene array. A decreased level of SNAP-25 was detected by quantitative real time-polymerase chain reaction and western blot assay at 1, 3, 7, 14 and 28 days post injury. SNAP-25 was localized in the cytoplasm of neurons of the anterior and posterior horns, which are involved in locomotor and sensory functions. Our data suggest that reduced levels of SNAP-25 are associated with sensory and locomotor functions in rats with spinal cord contusion injury.
