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The expression and function of the homeotic gene ultrabithorax in the bithorax complex of drosophila
Symposia Symposium 3: Genetic control of Drosophila development (91 -97)
91
92
THE HOMEOBOXAND THE 8ENETIO OONTROLOF THE BODY PLAN OF DROSOPHILA W.J. 6ehrilm. Bioze~trum, University of Basel,
%]~E EXPRESSIC~ A~D Ft~CTION OF T ~ HCMEOTIC GuTRABITHC~AX IN T ~ BITHORAX COMPLEX OF DF~SOPHILA. Robert A.H. ~ite. Department of Anatcmy, University of Cambrid~e~ Downing Street, Ca.brid~e, CB2 ~3Y, England.
Klingelbargstr. 70, OH-4056 Basel, Switzerland. The hsmeabox is a short DNA segmentof ~ 180 bp characteristic of homeotic genes and other genes centrolllng the body plan In Drosophila. It encodes 8 domain of the hemactic proteins which is thought to
The genes of the bithorax complex control the development of ~ne different ~ t types in d~e thorax and abdcmen of Drosophila. I ~ have identified the protein products of the Ultrabid~arax (Ubx) gene end described dleir distribution . How is this distribution generated and how do dne Uhx products flncticn to specify developmental ~dnweFs? The Ubx ~roteins are expressed in nuclei from the second thoracic ~ t to the eighd~ abdcminal segment (parase~mmts 5-13) in a heterogeneous pattern. Much of the h e t e r ~ e i t y is dependant on interacticns between Lqax and d~e othe~ genes of the bid-~rax ocmplex, abd-A and Abd-B-. The overall dcmain of Ubx ~icn is set ~0 early in development by ~%e action of the gap class of se~mentaticn genes . A picture is emerging of how the different features of the Ubx ~ i o n pattern - the overall dcmain, the repeat ~nits and the heterogeneity within the repeat units - are established by the gap, pair-rule and se~nent polarity classes of se~mentaticn genes. Bow the Ubx products function is at present umclear and we ere currently trying to identify the "downstream"
bind to specific DNA sequences in those genes that are controlled by theee proteins. This hypothesis is supported by sequence comparison with the alpha 2 repressor of yeast, In vitro DNA binding studies and
germline transformation with fusion genes. DNA sequence comp8rison suggests thai higher organisms Including men use similar genetic mechanisms to control development. 8enetic evidence indicates that homectic genes specify the identity and sequenceof the bodysegments. This hypothesis has been tested directly by reintroducing the clonedAntp genefused to e heat shock promoter into the germline of wildtypo flies. After heat induction during a precisely definedtime periode, the antennaeof the recipient flies becometransformed into second legs and the hindheed into mesothorax, indicating that Antp specifies the mesothoracic segment. Therefore, it is possible to alter the body plan of Drosophila by ectopic expression of the normal Antp gene in a predictable way and to "redesign the fruitfly".
genes regulated by Ubx. i. White and Wilcox (84), Cell 39, 163. 2. Struhl and White (85), Cell 43, 507. 3. White and LehTenn (86), Cell 47, 311. 34S
91
92
THE HOMEOBOXAND THE 8ENETIO OONTROLOF THE BODY PLAN OF DROSOPHILA W.J. 6ehrilm. Bioze~trum, University of Basel,
%]~E EXPRESSIC~ A~D Ft~CTION OF T ~ HCMEOTIC GuTRABITHC~AX IN T ~ BITHORAX COMPLEX OF DF~SOPHILA. Robert A.H. ~ite. Department of Anatcmy, University of Cambrid~e~ Downing Street, Ca.brid~e, CB2 ~3Y, England.
Klingelbargstr. 70, OH-4056 Basel, Switzerland. The hsmeabox is a short DNA segmentof ~ 180 bp characteristic of homeotic genes and other genes centrolllng the body plan In Drosophila. It encodes 8 domain of the hemactic proteins which is thought to
The genes of the bithorax complex control the development of ~ne different ~ t types in d~e thorax and abdcmen of Drosophila. I ~ have identified the protein products of the Ultrabid~arax (Ubx) gene end described dleir distribution . How is this distribution generated and how do dne Uhx products flncticn to specify developmental ~dnweFs? The Ubx ~roteins are expressed in nuclei from the second thoracic ~ t to the eighd~ abdcminal segment (parase~mmts 5-13) in a heterogeneous pattern. Much of the h e t e r ~ e i t y is dependant on interacticns between Lqax and d~e othe~ genes of the bid-~rax ocmplex, abd-A and Abd-B-. The overall dcmain of Ubx ~icn is set ~0 early in development by ~%e action of the gap class of se~mentaticn genes . A picture is emerging of how the different features of the Ubx ~ i o n pattern - the overall dcmain, the repeat ~nits and the heterogeneity within the repeat units - are established by the gap, pair-rule and se~nent polarity classes of se~mentaticn genes. Bow the Ubx products function is at present umclear and we ere currently trying to identify the "downstream"
bind to specific DNA sequences in those genes that are controlled by theee proteins. This hypothesis is supported by sequence comparison with the alpha 2 repressor of yeast, In vitro DNA binding studies and
germline transformation with fusion genes. DNA sequence comp8rison suggests thai higher organisms Including men use similar genetic mechanisms to control development. 8enetic evidence indicates that homectic genes specify the identity and sequenceof the bodysegments. This hypothesis has been tested directly by reintroducing the clonedAntp genefused to e heat shock promoter into the germline of wildtypo flies. After heat induction during a precisely definedtime periode, the antennaeof the recipient flies becometransformed into second legs and the hindheed into mesothorax, indicating that Antp specifies the mesothoracic segment. Therefore, it is possible to alter the body plan of Drosophila by ectopic expression of the normal Antp gene in a predictable way and to "redesign the fruitfly".
genes regulated by Ubx. i. White and Wilcox (84), Cell 39, 163. 2. Struhl and White (85), Cell 43, 507. 3. White and LehTenn (86), Cell 47, 311. 34S