Delta activity independent of its activity as a ligand of Notch.
BACKGROUND
Delta, Notch, and Scabrous often function together to make different cell types and refine tissue patterns during Drosophila development. Delta is known as the ligand that triggers Notch receptor activity. Scabrous is known to bind Notch and promote Notch activity in response to Delta. It is not known if Scabrous binds Delta or Delta has activity other than its activity as a ligand of Notch. It is very difficult to clearly determine this binding or activity in vivo as all Notch, Delta, and Scabrous activities are required simultaneously or successively in an inter-dependent manner.


RESULTS
Using Drosophila cultured cells we show that the full length Delta promotes accumulation of Daughterless protein, fringe RNA, and pangolin RNA in the absence of Scabrous or Notch. Scabrous binds Delta and suppresses this activity even though it increases the level of the Delta intracellular domain. We also show that Scabrous can promote Notch receptor activity, in the absence of Delta.


CONCLUSIONS
Delta has activity that is independent of its activity as a ligand of Notch. Scabrous suppresses this Delta activity. Scabrous also promotes Notch activity that is dependent on Delta's ligand activity. Thus, Notch, Delta, and Scabrous might function in complex combinatorial or mutually exclusive interactions during development. The data reported here will be of significant help in understanding these interactions in vivo.
Mok
Lee-Peng
LP
Department of Microbiology and Molecular Genetics, 322 Stafford Hall, 95 Carrigan Drive, The University of Vermont, Burlington, VT 05405, USA. lmok@uvm.edu <lmok@uvm.edu>
Qin
Tielin
T
Bardot
Boris
B
LeComte
Matthew
M
Homayouni
Asal
A
Ahimou
Francois
F
Wesley
Cedric
C
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002460:Cell Line; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D050437:Genes, Developmental; D017344:Genes, Insect; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D017351:N-Acetylglucosaminyltransferases / Q000235:genetics / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D011485:Protein Binding; D012313:RNA / Q000235:genetics; D051880:Receptors, Notch / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
D029721:Drosophila Proteins; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008565:Membrane Proteins; D051880:Receptors, Notch; D012097:Repressor Proteins; D014157:Transcription Factors; C064045:delta protein; C115159:pan protein, Drosophila; C066579:sca protein, Drosophila; D012313:RNA; D017351:N-Acetylglucosaminyltransferases; C090576:fng protein, Drosophila