No requirement for localized Nudel protein expression in Drosophila embryonic axis determination.
Drosophila embryonic dorsal-ventral polarity is defined by a maternally encoded signal transduction pathway. Gastrulation Defective, Snake, and Easter comprise a serine protease cascade that operates in the perivitelline space to generate active ligand for the Toll receptor, which resides in the embryonic membrane. Toll is activated only on the ventral side of the embryo. Spatial regulation of this pathway is initiated by the ventrally restricted expression of the sulfotransferase Pipe in the follicular epithelium that surrounds the developing oocyte. Pipe is thought to modify a target molecule that is secreted and localized within the ventral region of the egg and future embryo, where it influences the activity of the pathway such that active Toll ligand is produced only ventrally. A potential substrate for Pipe is encoded by nudel, which is expressed throughout the follicle cell layer and encodes a large, multi-functional secreted protein that contains a serine protease domain as well as other structural features characteristic of extracellular matrix proteins. A previous mosaic analysis suggested that the protease domain of Nudel is not a target for Pipe activity as its expression is not required in pipe-expressing cells, but failed to rule out such a role for other functional domains of the protein. To investigate this possibility, we carried out a mosaic analysis of additional nudel alleles, including some that affect the entire protein. Our analysis demonstrated that proteolytically processed segments of Nudel are secreted into the perivitelline space and stably localized, as would be expected for the target of Pipe, However, we found no requirement for nudel to be expressed in ventral, pipe-expressing follicle cells, thereby eliminating Nudel as an essential substrate of Pipe sulfotransferase activity.
Stein
David
D
Section of Molecular Cell and Developmental Biology and Institute for Cellular and Molecular Biology; University of Texas at Austin; Austin, Texas, USA. d.stein@mail.utexas
Cho
Yong Suk
YS
Zhang
Zhenyu
Z
Stevens
Leslie M
LM
D000483:Alleles; D000818:Animals; D002470:Cell Survival; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D047108:Embryonic Development; D000939:Epitopes / Q000378:metabolism; D005260:Female; D006080:Ovarian Follicle / Q000378:metabolism; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D015238:Sulfotransferases / Q000378:metabolism*
D029721:Drosophila Proteins; D000939:Epitopes; D015238:Sulfotransferases; C115847:pip protein, Drosophila; D012697:Serine Endopeptidases; C115869:ndl protein, Drosophila
Cell. 1989 Nov 3;59(3):499-509
2509077
Genetics. 1996 Aug;143(4):1653-61
8844153
EMBO J. 2001 May 15;20(10):2387-93
11350927
J Biol Chem. 1997 May 23;272(21):13980-5
9153262
Curr Top Dev Biol. 1999;44:203-43
9891881
Development. 1992 Jun;115(2):607-16
1425342
Cell. 1985 Oct;42(3):779-89
3931918
Proc Natl Acad Sci U S A. 1987 May;84(10):3194-8
3472204
J Biol Chem. 1999 Apr 9;274(15):10474-80
10187838
Development. 2005 Sep;132(17):3813-22
16049108
Genes Dev. 1993 Dec;7(12B):2548-55
8276237
Development. 1998 Jun;125(12):2263-71
9584125
Proc Natl Acad Sci U S A. 1998 Jun 9;95(12):6819-24
9618496
Development. 2004 Feb;131(4):775-86
14724122
Development. 1998 Oct;125(20):4045-53
9735365
Dev Genes Evol. 2001 Dec;211(12):573-80
11819114
Nature. 1994 Apr 7;368(6471):548-51
8139688
Proc Natl Acad Sci U S A. 2000 Aug 1;97(16):9093-7
10922064
DNA Cell Biol. 1999 Jun;18(6):457-62
10390154
Dev Biol. 2006 May 1;293(1):127-41
16515779
Trends Cell Biol. 2008 Jul;18(7):315-21
18524595
Cell. 1984 Nov;39(1):27-38
6091915
Curr Biol. 2003 Jun 17;13(12):1058-63
12814553
Dev Biol. 2000 Jan 15;217(2):352-61
10625559
Cell. 1998 Apr 17;93(2):253-62
9568717
Curr Biol. 2005 Nov 8;15(21):R887-99
16271864
Development. 2007 Apr;134(8):1465-9
17344226
Cell. 1998 Nov 13;95(4):471-81
9827800
Genes Dev. 1988 Mar;2(3):341-9
3378704
Genetics. 2000 Jan;154(1):247-57
10628985
Nature. 1986 Oct 23;323(6090):688-92
11486795
Genes Dev. 2002 Apr 15;16(8):913-8
11959840
EMBO Rep. 2001 Aug;2(8):721-6
11493599
Proc Natl Acad Sci U S A. 2001 Apr 24;98(9):5055-60
11296245
Cell. 1995 Sep 8;82(5):785-94
7671306
Nature. 1994 Feb 24;367(6465):741-5
8107870
Cell. 1989 Feb 10;56(3):391-400
2492450