L. Seroude (2002) Full text
"GAL4 drivers expression in the whole adult fly"
Genesis, 34, 34-38

L. Seroude, T. Brummel, P. Kapahi and S. Benzer (2002) Full text
"Spatio-temporal analysis of gene expression during aging in Drosophila melanogaster"
Aging Cell, 1, 47-56

The relationship between gene expression and the regulation of longevity is poorly understood. Previous studies focusing on microarray or tissue-specific changes in gene expression as a function of age have provided evidence that gene expression is a dynamic process which is regulated, even late in an organism's lifespan. Using the enhancer-trap technique, a systematic analysis of the spatio-temporal regulation of gene expression in tissues of adult Drosophila is presented. As many as 80% of enhancer traps analysed displayed (some form of) transcriptional change with age. In some cases the rate of change in expression was found to correlate with changes in longevity under various conditions, suggesting that they may be indicators of 'physiological age' and therefore valuable markers for dissecting the aging process. Molecular analysis of enhancer traps that showed increased activity with age was performed to identify candidate genes that may be important in the regulation of longevity; we identified changes in reporters associated with immunity, microtubule organization and muscle function.

1. C. J. O'Kane and W. J. Gehring (1987)
Detection in situ of genomic regulatory elements in Drosophila
Proc Natl Acad Sci U S A, 84, 24, 9123-7

We have developed an approach for the in situ detection of genomic elements that regulate transcription zin Drosophila melanogaster. The approach is analogous to a powerful method of bacterial genetics, the random generation of operon fusions, that enables the isolation and characterization of genes simply by knowing or postulating their pattern of expression; it is not necessary initially to screen for mutant phenotypes. To apply this approach to Drosophila, we have used the expression of the lacZ gene of Escherichia coli from the P-element promoter in germ-line transformant flies to screen for chromosomal elements that can act at a distance to stimulate expression from this apparently weak promoter. Of 49 transformed fly lines obtained, approximately 70% show some type of spatially regulated expression of the lacZ gene in embryos; many of these express lacZ specifically in the nervous system. The P-lacZ fusion gene is, therefore, an efficient tool for the recovery of elements that may regulate gene expression in Drosophila and for the generation of a wide variety of cell-type- specific markers.

2. A. H. Brand and N. Perrimon (1993)(Full Text)
Targeted gene expression as a means of altering cell fates and generating dominant phenotypes
Development, 118, 2, 401-415

We have designed a system for targeted gene expression that allows the selective activation of any cloned gene in a wide variety of tissue- and cell-specific patterns.^The gene encoding the yeast transcriptional activator GAL4 is inserted randomly into the Drosophila genome to drive GAL4 expression from one of a diverse array of genomic enhancers.^It is then possible to introduce a gene containing GAL4 binding sites within its promoter, to activate it in those cells where GAL4 is expressed, and to observe the effect of this directed misexpression on development.^We have used GAL4-directed transcription to expand the domain of embryonic expression of the homeobox protein even-skipped.^We show that even-skipped represses wingless and transforms cells that would normally secrete naked cuticle into denticle secreting cells.^The GAL4 system can thus be used to study regulatory interactions during embryonic development.^In adults, targeted expression can be used to generate dominant phenotypes for use in genetic screens.^We have directed expression of an activated form of the Dras2 protein, resulting in dominant eye and wing defects that can be used in screens to identify other members of the Dras2 signal transduction pathway.

3. J. A. Simon and J. T. Lis (1987)
A germline transformation analysis reveals flexibility in the organization of heat shock consensus elements
Nucleic Acids Res, 15, 7, 2971-88

Maximal expression of the Drosophila heat shock gene hsp70 can be activated by a pair of heat shock consensus elements (HSE's) positioned close to the transcription start site. In contrast, required HSE's of other heat shock genes (i.e., hsp26, 27, 23) are located several hundred base pairs (bp) farther upstream of their start sites. Using germline transformation, we analyzed the requirements for HSE organization in the hsp70 and hsp26 regulatory regions. A 51 bp fragment containing the two proximal hsp70 HSE's was sufficient to rescue the heat shock response of an hsp26-lacZ gene devoid of its HSE's. Heat inducibility was restored with either orientation of the fragment relative to the hsp26 transcription start. In hsp70 gene constructions, relocation of hsp70 HSE's to more remote positions by inserting 127 or 331 bp into the regulatory region failed to substantially reduce expression. Thus, in contrast to their native configurations, the hsp26 promoter can be activated by HSE's solely in a proximal position and the hsp70 promoter can be activated by remote HSE's. In addition, a simple and sensitive assay for quantitative measurement of beta-galactosidase activity in crude fly extracts is described.

4. M. Ashburner (1989)
Drosophila A Laboratory Handbook.
Cold Spring Harbor Laboratory Press

5. B. Dysvik and I. Jonassen (2001)(Full Text)
J-Express: exploring gene expression data using Java
Bioinformatics 17, 4, 369-70

J-Express is a Java application that allows the user to analyze gene expression (microarray) data in a flexible way giving access to multidimensional scaling, clustering, and visualization methods in an integrated manner. Specifically, J-Express includes implementations of hierarchical clustering, k-means, principal component analysis, and self-organizing maps. At present, it does not include methods for comparing two or more experiments for differentially expressed genes. The application is completely portable and requires only that a Java runtime environment 1.2 is installed on the system. Its efficiency allows interactive clustering of thousands of expression profiles on standard personal computers.

6. B.A. Hamilton and K. Zinn (1994)
From clone to mutant gene
Methods Cell Biol 44, 81-94