Fat regulates expression of four-jointed reporters in vivo through a 20 bp element independently of the Hippo pathway

• Published in: Developmental biology 2019-06, Vol.450 (1), p.23-33
• Main Authors: Arbouzova, Natalia I., Fulford, Alexander D., Zhang, Hongtao, McNeill, Helen
• Format: Article
• Language: English
• Subjects: Animals; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - metabolism; Drosophila melanogaster; Drosophila Proteins - biosynthesis; Drosophila Proteins - genetics; Drosophila Proteins - metabolism; Enhancer; Enhancer Elements, Genetic; Eye imaginal disc; Fat; Four-jointed; Gene Expression Regulation, Developmental; Genes, Reporter; Hippo pathway; Intracellular Signaling Peptides and Proteins - genetics; Intracellular Signaling Peptides and Proteins - metabolism; Membrane Glycoproteins - biosynthesis; Membrane Glycoproteins - genetics; Planar cell polarity; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Signal Transduction; Transcription, Genetic
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/j.ydbio.2019.03.004

Development of an organism requires accurate coordination between the growth of a tissue and orientation of cells within the tissue. The large cadherin Fat has been shown to play a role in both of these processes. Fat is involved in the establishment of planar cell polarity and regulates growth through the Hippo pathway, a developmental cascade that controls proliferation and apoptosis. Both Fat and the Hippo pathway are known to regulate transcription of four-jointed, although the nature of this regulation is unknown. In this study, we test whether Fat affects four-jointed transcription via or independently of Hippo pathway. Our analysis of the four-jointed regulatory region reveals a 1.2 kb element that functions as an enhancer for graded expression of Four-jointed in the eye imaginal disc. Within this enhancer element, we identify a 20 bp fragment that is critical for regulation by Fat but not by Hippo. Our findings suggest that Fat and the Hippo pathway control four-jointed expression independently of each other and none of the transcription factors known to function downstream of the Hippo pathway are required to regulate four-jointed expression through the 1.2 kb element. •Four-jointed genomic region contains a 1.2 kb eye enhancer located downstream of the coding region.•The eye enhancer is sensitive to Notch, WNT, JAK/STAT, Hippo, and Fat.•Fat controls the four-jointed eye enhancer through a 20 bp element.•Fat and Hippo response elements overlap, but are separable.