Abstract
The establishment of anterior-posterior and dorsal-ventral polarity during oogenesis of Drosophila requires the precise regulation of the spatial and temporal activation and inhibition of epidermal growth factor receptor (Egfr) signaling pathway which plays a key role to induce differentiation with its duration and intensity. To find out more molecules which are involved in the Egfr pathway, screen for P lines that show expression patterns mimicking the Egfr activation was carried out in the past. Among four selected lines, P1542 was observed with positive staining in dorsoanterior follicle cells of egg chambers at stage 9 and 10. Ectopic staining was detected within CY2Gal4 or T155Gal4 driven UAS-λtop4.2, a constitutively active Egfr, females. On the contrary, overexpression of Argos significantly inhibits the staining pattern of P1542. For the identification of that if P1542 influence the Egfr signaling, somatic mosaic clones for P1542 were created. Abnormal development of dorsal appendages is caused by the homozygous mutant clones of P1542. However, using P1542 itself and Ra5 as readout of Egfr signaling, there was a non-significant effect. Thus we conjecture that P1542 is regulated by Egfr signaling and further influence the development process of dorsal appendages without implicating in the feedback loop. For the purpose of the determination of the gene that P1542 affects, we performed in situ hybridizations of blot and cg3885. From the results, blot is not expressed in follicle cells and cg3885 is expressed but only in few cells. More evidences and a thorough inquiry are needed for the confirmation that whether these two genes are regulated by the Egfr signaling and if P1542 mimics another gene.