PMID- 8951053
OWN - NLM
STAT- MEDLINE
DCOM- 19970123
LR  - 20220215
IS  - 0950-1991 (Print)
IS  - 0950-1991 (Linking)
VI  - 122
IP  - 11
DP  - 1996 Nov
TI  - The Drosophila embryonic midline is the site of Spitz processing, and induces 
      activation of the EGF receptor in the ventral ectoderm.
PG  - 3363-70
AB  - The Drosophila EGF receptor (DER) is activated by secreted Spitz to induce 
      different cell fates in the ventral ectoderm. Processing of the precursor 
      transmembrane Spitz to generate the secreted form was shown to be the limiting 
      event, but the cells in which processing takes place and the mechanism that may 
      generate a gradient of secreted Spitz in the ectoderm were not known. The 
      ectodermal defects in single minded (sim) mutant embryos, in which the midline 
      fails to develop, suggested that the midline cells contribute to patterning of 
      the ventral ectoderm. This work shows that the midline provides the site for 
      Spitz expression and processing. The Rhomboid and Star proteins are also 
      expressed and required in the midline. The ectodermal defects of spitz, rho or 
      Star mutant embryos could be rescued by inducing the expression of the respective 
      normal genes only in the midline cells. Rho and Star thus function 
      non-autonomously, and may be required for the production or processing of the 
      Spitz precursor. Secreted Spitz is the only sim-dependent contribution of the 
      midline to patterning the ectoderm, since the ventral defects observed in sim 
      mutant embryos can be overcome by expression of secreted Spitz in the ectoderm. 
      While ectopic expression of secreted Spitz in the ectoderm or mesoderm gave rise 
      to ventralization of the embryo, increased expression of secreted Spitz in the 
      midline did not lead to alterations in ectoderm patterning. A mechanism for 
      adjustment to variable levels of secreted Spitz emanating from the midline may be 
      provided by Argos, which forms an inhibitory feedback loop for DER activation. 
      The production of secreted Spitz in the midline, may provide a stable source for 
      graded DER activation in the ventral ectoderm.
FAU - Golembo, M
AU  - Golembo M
AD  - Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
FAU - Raz, E
AU  - Raz E
FAU - Shilo, B Z
AU  - Shilo BZ
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Development
JT  - Development (Cambridge, England)
JID - 8701744
RN  - 0 (Drosophila Proteins)
RN  - 0 (Membrane Proteins)
RN  - 0 (Phosphoproteins)
RN  - 0 (Rho protein, Drosophila)
RN  - 0 (Stet protein, Drosophila)
RN  - 0 (steroidogenic acute regulatory protein)
RN  - 148175-53-5 (spi protein, Drosophila)
RN  - 62229-50-9 (Epidermal Growth Factor)
RN  - EC 2.7.10.1 (ErbB Receptors)
SB  - IM
MH  - Animals
MH  - Cell Differentiation
MH  - *Drosophila Proteins
MH  - Drosophila melanogaster/*embryology
MH  - Ectoderm/physiology
MH  - *Epidermal Growth Factor
MH  - ErbB Receptors/*physiology
MH  - *Gene Expression Regulation, Developmental
MH  - Membrane Proteins/*physiology
MH  - Mesoderm/physiology
MH  - Morphogenesis
MH  - Phosphoproteins/physiology
EDAT- 1996/11/01 00:00
MHDA- 1996/11/01 00:01
CRDT- 1996/11/01 00:00
PHST- 1996/11/01 00:00 [pubmed]
PHST- 1996/11/01 00:01 [medline]
PHST- 1996/11/01 00:00 [entrez]
AID - 10.1242/dev.122.11.3363 [doi]
PST - ppublish
SO  - Development. 1996 Nov;122(11):3363-70. doi: 10.1242/dev.122.11.3363.