Terminal pattern elements in Drosophila embryo induced by the torso-like protein

• DOI: 10.1038/367741a0
• Publication Date: 2003-08-12T18:48:29Z
• Authors: Jean-René Martin; Anna Raibaud; Roger Ollo
• Keywords: MESH: Ovary; Male; 0301 basic medicine; MESH: Mutation; MESH: Drosophila; MESH: Drosophila Proteins; Molecular Sequence Data; Restriction Mapping; Genes, Insect; MESH: Amino Acid Sequence; MESH: Genes, Insect; MESH: Base Sequence; MESH: Protein-Tyrosine Kinases; 03 medical and health sciences; MESH: In Situ Hybridization; MESH: Insect Hormones; MESH: Blotting, Southern; Morphogenesis; Animals; Drosophila Proteins; MESH: Animals; [SDV.NEU] Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]; Amino Acid Sequence; RNA, Messenger; MESH: Restriction Mapping; In Situ Hybridization; MESH: RNA, Messenger; MESH: Molecular Sequence Data; Base Sequence; Ovary; Chromosome Mapping; Receptor Protein-Tyrosine Kinases; Protein-Tyrosine Kinases; MESH: Male; MESH: Morphogenesis; Blotting, Southern; Insect Hormones; Mutation; MESH: Receptor Protein-Tyrosine Kinases; [SDV.NEU]Life Sciences [q-bio]/Neurons and Cognition [q-bio.NC]; Drosophila; Female; MESH: Chromosome Mapping; MESH: Female

The genes torso (tor) and torso-like (tsl) are two of the Drosophila maternal group genes implicated in a receptor tyrosine kinase signalling pathway that specifies terminal cell fate (reviewed in ref. 3). Loss-of-function mutations in these loci cause an identical phenotype in which pattern elements from the anterior (acron) and posterior (telson) ends have been deleted. We have cloned the tsl gene and demonstrate here that, in agreement with previous genetic data, it encodes a protein that is secreted and whose transcription is restricted to specialized categories of follicle cells localized at the poles of the egg chamber. At early blastoderm stage, tsl protein forms a symmetrical concentration gradient at the poles on the surface of the devitellinized embryo. Unrestricted expression of the tsl protein in tsl female mutants induces terminal pattern elements and suppresses the formation of abdomen in embryos. These results suggest that the tsl protein is the ligand that binds to the torso receptor.