N-terminal immunoreactivity in the senile plaques was noted along the periphery of the senile plaques, while that for Affi28 was around the amyloid core. Thus, each fragment of APP exhibited a different localization and time course of immunohistochemical expression. The results indicated that APP plays a role in neuronal development and that its earlier reappearance in adult DS patients is associated with the regeneration process related to aging. Mutations of the drop-dead gene in Drosophila melanogaster lead to striking early death of the adult animal. At different times, after emergence from the pupa, individual flies begin to stagger and, shortly thereafter, die.
Anatomical examination reveals gross neuropathological lesions in the brain.
The life span of flies mutant for the drop-dead gene is four to five times shorter than for normal adults. That raises the question whether loss of the normal gene product might set into motion a series of events typical of the normal aging process. We used molecular markers, the expression patterns of which, in normal flies, change with age in a manner that correlates with life span. Mismatch repair in extracts of Werner syndrome cell lines. WS cells and cell lines display several types of genetic instability, and WS patients have an increased risk of developing cancer.