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Conservation of heterochromatin protein 1 function
1Chromatin Function Laboratory, The Babraham Institute, Babraham, Cambridge, United Kingdom.
Molecular and Cellular Biology
|August 25, 2000
Summary
Heterochromatin protein 1 (HP1) self-association is key for gene silencing. Its chromodomain function is conserved across species, highlighting critical hydrophobic residues for biological activity.
Area of Science:
- Molecular Biology
- Genetics
- Cell Biology
Background:
- Heterochromatin mediates heritable gene repression.
- Swi6 protein (HP1-like) in yeast (Schizosaccharomyces pombe) localizes to and silences heterochromatin domains.
Purpose of the Study:
- Identify functional domains of Swi6p.
- Investigate conservation of chromodomain function.
- Determine the role of Swi6p structure in function.
- Explore HP1 self-association and its role in heterochromatin.
Main Methods:
- Site-directed mutagenesis based on modeled 3D structure.
- Functional assays of Swi6p domains.
- Heterologous complementation with mammalian HP1 (M31).
- Biochemical analyses: gel filtration, gel overlay, mass spectroscopy.
Main Results:
- Mammalian M31 HP1 chromodomain functionally replaces Swi6p chromodomain, indicating conserved function.
- Hydrophobic amino acids in the Swi6p chromodomain core are critical for biological activity.
- HP1 proteins demonstrate self-association capabilities.
Conclusions:
- Chromodomain function in heterochromatin formation is conserved from yeast to humans.
- Self-association into oligomers is proposed as the mechanism for HP1 incorporation into silencing complexes.