We have found that during aging the basal expression of these genes is upregulated at both the transcriptional and posttranscriptional levels, with characteristic temporal and spatial patterns. Induction appears to be in part due to oxidative stress. Recent data from other labs demonstrates that a similar pattern of hsp expression is occurring in aging mammals. We are pursuing a detailed analysis of the transcriptional and posttranscriptional regulation of the Drosophila hsp70 and hsp22 genes as a model for this species-general aspect of aging. Chorion gene amplification Chorion gene amplification provides an ideal model for the regulation of higher eukaryotic chromosomal DNA replication origins.
Amplification occurs by repeated firing of one or more origins located within each gene cluster.
We have cloned and characterized two amplification trans-regulators, k43 and chiffon , and found that they are related to origin regulatory proteins in yeasts, ORC2 and Dbf4 respectively. The data implicated chromatin structure in origin regulation, and provided a powerfully improved assay. Using such buffered constructs we have been able to analyze cis -sequence requirements and functions in detail. We have found that functionally distinct, sequence-specific replicator and origin elements are required for amplification. The k43 gene, required for chorion gene amplification and diploid cell chromosome replication, encodes the Drosophila homolog of yeast origin recognition complex subunit 2.