الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
There are genes whose sequence is known but function remains unknown. The elucidation of gene function must always be verified in vivo using genetic analysis. Reverse genetics is a powerful tool that establishes a direct link between the biochemical function of a gene product and its role in vivo. One of the most important genetic systems used in reverse genetic approaches in Drosophila is the upstream activation sequence UAS/ GAL4 system.
The present study aimed to screen the implication of five genes (Neb, Ctcfi, Sense, Tao, Lis-1) in axis formation of Drosophila using the UAS /GAL4 system. The obtained results indicated that the studied genes showed different effects on axis formation. In general, all the studied genes caused missing of abdominal segments. Neb and Lis-1genes showed completely lacks of head structures and often missing of anterior thoracic structure leaving a large hole in the head cuticle. While Tao and Ctcfi illustrated denticle abnormalities ranged from embryos with mild defects that had missing or fused abdominal denticle belts. On the other case, (Neb, Sense, Lis-1 and Tao) elucidated lack of posterior terminal structures and filzkörpers.
Immunostaining technique for protein using even–skipped (eve) and bicoid (bcd) antibody were used in this study. The obtained results indicated that three of the genes under study neb, Tao and Ctcfi have an effect on the distribution of the maternal bicoid protein (bcd), where the concentration and distribution of bicoid protein was decreased compared with control.
While the inhibition of these genes showed disruption of the normal eve pattern. Where, we observed severe defects in stripe intensity and width, whereas their spacing appeared irregular in the same age compared with control. While the inhibition of sens or Lis1genes didn’t effect significantly on the distribution of the bicoid protein or eve stripe pattern formation. These results, indicated that the role of these genes in the next stage for embryo development. The overall data showed that the investigated genes play an essential role in Drosophila axis.