D. melanogaster imaginal disk mitotic abnormalities induced by a tumor-suppressor Dlg-silencing construction

Abstract

Mitosis, cytokinesis and nuclear texture of wing imaginal disk cells silenced by UAS-RNAi-dlg construct activated by a 1096-Gal4 driver were studied. The construct is a P-element genomic insertion with a UAS-promoter driving the silencing element. The latter contains a coding region of the dlg gene and complementary region. They produce an RNA hairpin processed by the endogenous protein Dicer (Dietzl et al., 2007). The resulting RNA fragments silence dlg mRNA. The complex is cleaved with the genomic Dicer, and dlg mRNA disintegrates. The tumor suppressor gene dlg encodes 21 transcripts. The construct UAS-RNAi-dlg inactivates 14 transcripts (RE, RH, RQ, RS, RG, RD, RL, RB, RK, RR, RT, RN, RA, RP) and does not silence 7 others (RO, RF, RI, RU, RJ, RC, RM). This permits one to study the function of proteins containing guanilate-kinase domain IPR008145 at the protein C-end. The most important consequences of the silencing are the abnormal mitoses exit and binuclear cells formation. Quantitative fluorescence measurements of anti-H3-p histone and DAPI signals showed phase-specific changes in nuclear texture. The most probable dlg target is inactivation of cellular cortex polarization in mitosis.