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Genetic and molecular analysis of the drosophila melanogaster polycomb group gene additional sex combs Milne, Thomas Arthur
Abstract
Proteins of the trithorax group (trxG) and the Polycomb group (PcG) maintain the spatially restricted active and repressed states respectively of the homeotic genes throughout development. Mutations in PcG genes cause homeotic genes to be ectopically expressed which generally results in posterior homeotic transformations. Mutations in trxG genes have the opposite effect. They reduce homeotic gene expression and generally cause anterior transformations. Mutations in trxG and PcG genes mutually suppress each others homeotic transformations, suggesting that the two groups of proteins either act antagonistically or that they have opposite and independent functions. Additional sex combs (Asx) can enhance both trxG and PcG homeotic mutations, suggesting that Asx is important for both activation and repression of the homeotic loci. In addition, Asx has both tissue and stage specific effects on homeotic gene regulation.To gain further insight into Asx function, I used antibodies to the Asx protein to examine its expression pattern in embryos and to show that Asx protein binds to sites on polytene chromosomes containing other P cG proteins, but that it also binds to some unique target sites. Asx protein is probably part of a large PcG complex that binds to many target sites but the fact that it can bind to some unique target sites also indicates that it may be a member of other non-PcG protein complexes. To identify and clone genes important for Asx activity, interactor cDNAs from a yeast 2 hybrid screen were mapped to specific chromosomal sites. A large deletion (Df[3L)ZN4T) that removes the locus of the z40 interactor genetically interacts with Asx and shows target specific homeotic regulatory defects. Also, the PcG gene super sex combs (sxc) shows a strong genetic interaction with Asx and an attempt was made to transposon tag and clone sxc. These results suggest that Asx is a component of both repression and activation and that its stage and tissue specific activities are modulated by interactions with specific protein subsets such as z40.
Item Metadata
Title |
Genetic and molecular analysis of the drosophila melanogaster polycomb group gene additional sex combs
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1998
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Description |
Proteins of the trithorax group (trxG) and the Polycomb group (PcG) maintain the
spatially restricted active and repressed states respectively of the homeotic genes throughout
development. Mutations in PcG genes cause homeotic genes to be ectopically expressed
which generally results in posterior homeotic transformations. Mutations in trxG genes
have the opposite effect. They reduce homeotic gene expression and generally cause
anterior transformations. Mutations in trxG and PcG genes mutually suppress each others
homeotic transformations, suggesting that the two groups of proteins either act
antagonistically or that they have opposite and independent functions. Additional sex
combs (Asx) can enhance both trxG and PcG homeotic mutations, suggesting that Asx is
important for both activation and repression of the homeotic loci. In addition, Asx has both
tissue and stage specific effects on homeotic gene regulation.To gain further insight into
Asx function, I used antibodies to the Asx protein to examine its expression pattern in
embryos and to show that Asx protein binds to sites on polytene chromosomes containing
other P cG proteins, but that it also binds to some unique target sites. Asx protein is
probably part of a large PcG complex that binds to many target sites but the fact that it can
bind to some unique target sites also indicates that it may be a member of other non-PcG
protein complexes. To identify and clone genes important for Asx activity, interactor
cDNAs from a yeast 2 hybrid screen were mapped to specific chromosomal sites. A large
deletion (Df[3L)ZN4T) that removes the locus of the z40 interactor genetically interacts
with Asx and shows target specific homeotic regulatory defects. Also, the PcG gene super
sex combs (sxc) shows a strong genetic interaction with Asx and an attempt was made to
transposon tag and clone sxc. These results suggest that Asx is a component of both
repression and activation and that its stage and tissue specific activities are modulated by
interactions with specific protein subsets such as z40.
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Extent |
9513031 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-04-30
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0088433
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1998-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.