Suppressors of a hyperplastic Drosophila Ras85DV12 phenotype were isolated using Ras85DV12 clones in the developing eye. An amorphic allele of Ptip was isolated in this screen. Although loss of Ptip expression suppresses growth in a cell-intrinsic manner, it was found to cooperate with oncogenic Ras85D to promote overgrowth of the surrounding tissue. It was determined that the nonautonomous effects of Ptip are mediated by Dmel\p53. Direct overexpression of wild-type p53 in clones of Ras85DV12 cells is sufficient to trigger the overgrowth of the surrounding wild-type tissue, mimicking Ras85DV12 Ptip-null clones. The ability of p53 to drive nonautonomous tissue overgrowth requires oncogenic Ras85D; overexpression of p53 alone fails to generate a similar effect.
Ras85DV12 is a constitutively activated form that has been used extensively in Drosophila models of cancer; see the human disease model report 'cancer, multiple, RAS-related' (FBhh0000474) and related diseases. The G12V mutation in Ras85DV12 is analogous to oncogenic mutations in human KRAS, HRAS and NRAS.
Dmel\Ptip is orthologous to the human gene PAXIP1, which encodes a nuclear protein involved in DNA damage response.
Dmel\p53 is orthologous to human TP53, TP63 and TP73. Of particular interest is TP53, which has been associated with many cancer types. TP53 is a transcriptional activator involved in the response to cellular stress. See the human disease model 'cancer, multiple, TP53-related' (FBhh0000340).
[updated May 2021 by FlyBase; FBrf0222196]
The TP53 gene encodes a tumor suppressor protein containing transcriptional activation, DNA binding, and oligomerization domains. The encoded protein responds to diverse cellular stresses to regulate expression of target genes, thereby inducing cell cycle arrest, apoptosis, senescence, DNA repair, or changes in metabolism. Mutations in this gene are associated with a variety of human cancers. [Gene Cards, TP53, 2021.05.20]
PAXIP1 is a member of the paired box (PAX) gene family and encodes a nuclear protein involved in DNA damage response and in transcriptional regulation through histone methyltransferase (HMT) complexes. [Gene Cards, PAXIP1; 2021.05.20]
Many to one: 3 human to 1 Drosophila; additional orthologous human genes are TP63 and TP73.
High-scoring ortholog of human genes TP53, TP63 and TP73 (1 Drosophila to 3 human). Dmel\p53 shares 20-24% identity and 36-41% similarity with the human genes.
High-scoring ortholog of human PAXIP1 (1 Drosophila to 1 human). Dmel\Ptip shares 27% identity and 41% similarity with the human gene.