NSF Award
9304866
Chromosomes of eukaryotes have regions of differing compaction termed heterochromatin and euchromatin. Heterochromatin has a high density of repetitious DNA, few genes and little transcription. Active genes, most of which are found in the euchromatin, are inactivated if they are removed to heterochromatic regions. This effect, called position effect variegation (PEV), has been extensively studied in Drosophila melanogaster, the fruit fly. There is evidence that the telomeric regions at the ends of eukaryotic chromosomes are specialized heterochromatic-like domains. The project proposed uses telomeric PEV in Drosophila to investigate telomeric chromatin by identification of telomeric non- histone proteins and telomeric DNA sequences which bind those proteins. A white eye color gene flanked by telomeric sequences will be integrated at non-telomeric locations and the expression of that gene with and without the telomeric sequences will be compared. A second approach will be to localize the DNA sequences necessary and/or sufficient to bind HP1, a protein characterized in other laboratories, which is implicated in chromatin condensation. %%% The primary objective of this project is to identify telomeric proteins and the DNA sequences to which they bind, but the resulting data will also be relevant to the broader question of how gene expression is regulated by chromosome condensation. Such a mechanism is thought to be critical to normal development of eukaryotic organisms.
