This model of epithelial cancer uses the Drosophila Scribble polarity complex gene l(2)gl in combination with the fly ortholog of the human MYC oncogene, Dmel\Myc. The highly conserved Scribble polarity complex plays a key role in determining cell polarity and cell proliferation in epithelial cells. MYC encodes a transcription factor that plays a role in cell cycle progression, apoptosis and cellular transformation.
Animals homozygous for loss-of-function mutations of Dmel\l(2)gl typically die during the larval stage and exhibit abnormal overproliferation of multiple tissues. Epithelial phenotypes have been assessed using mosaic clones in wing imaginal discs. Somatic clones that are homozygous for loss-of-function mutations of l(2)gl generated in wild-type imaginal discs are eliminated or reduced to very small size. When clones carrying both a loss-of-function mutation of l(2)gl and an over-expression allele of Dmel\Myc are generated, significant overgrowth is observed for clones located in the proximal part of the disc, but not for clones located in the distal part of the disc. The overproliferating clones exhibit impaired apical-basal polarity and disruptions to the basement membrane.
Transgenes of the human genes Hsap\MYC and Hsap\LLGL1 have been introduced into flies. In both cases, partial heterologous rescue (functional complementation) has been demonstrated.
See also human disease model reports 'cancer, epithelial, LLGL-related' (FBhh0000591) and 'cancer, multiple, MYC-related' (FBhh0000402).
[updated Nov. 2020 by FlyBase; FBrf0222196]
LLGL1 and LLGL2 encode cortical cytoskeleton proteins found in a complex involved in maintaining cell polarity and epithelial integrity, the Scribble Cell Polarity Complex. This complex plays a role in the initial phase of the establishment of epithelial cell polarity; it is involved in the regulation of mitotic spindle orientation, proliferation, differentiation, and tissue organization of neuroepithelial cells. [Gene Cards, LLGL1, LLGL2; 2020.11.10]]
MYC encodes a transcription factor that plays a role in cell cycle progression, apoptosis and cellular transformation. [Gene Cards, MYC; 2020.11.10]
Many to one: 2 human genes to 1 Drosophila gene; the second human gene is LLGL1.
Many to one: 2 human genes to 1 Drosophila gene; the second human gene is LLGL2.
Many to one : 3 human genes to 1 Drosophila gene; additional (lower-scoring) human orthologs are MYCN and MYCL.
Moderate- to high-scoring ortholog of human LLGL1 and LLGL2 (1 Drosophila to 2 human). Dmel\l(2)gl shares 34-36% identity and 51-54% similarity with the human genes.
Orthologous to human gene MYC (reciprocal best hit); lower scoring ortholog of human MYCN and MYCL (1 Drosophila to 3 human). Dmel\Myc shares 31% identity and 44% similarity with human MYC, within the carboxy extents of the two proteins.