The fully linked HTML version of this article has now been published.
Development ePress online publication date 16 Aug 2006
doi: 10.1242/dev.02525
Research article
Fork head and Sage maintain a uniform and patent salivary gland lumen through regulation of two downstream target genes, PH4
SG1 and PH4
SG2
Elliott W. Abrams,
Whitney K. Mihoulides,
and
Deborah J. Andrew*
* Author for correspondence (e-mail: dandrew{at}jhmi.edu)
(Fkh) is required to block salivary gland apoptosis, internalize salivary gland precursors, prevent expression of duct genes in secretory cells and maintain expression of CrebA, which is required for elevated secretory function. Here, we characterize two new Fkh-dependent genes: PH4
SG1 and PH4
SG2. We show through in vitro DNA-binding studies and in vivo expression assays that Fkh cooperates with the salivary gland-specific bHLH protein Sage to directly regulate expression of PH4
SG2, as well as sage itself, and to indirectly regulate expression of PH4
SG1. PH4
SG1 and PH4
SG2 encode
-subunits of resident ER enzymes that hydroxylate prolines in collagen and other secreted proteins. We demonstrate that salivary gland secretions are altered in embryos missing function of PH4
SG1 and PH4
SG2; secretory content is reduced and shows increased electron density by TEM. Interestingly, the altered secretory content results in regions of tube dilation and constriction, with intermittent tube closure. The regulation studies and phenotypic characterization of PH4
SG1 and PH4
SG2 link Fkh, which initiates tube formation, to the maintenance of an open and uniformly sized secretory tube.

CiteULike
Complore
Connotea
Del.icio.us
Digg
Reddit
Technorati
Twitter What's this?
This article has been cited by other articles:

|
 |

|
 |
 
Q. Xia, Y. Guo, Z. Zhang, D. Li, Z. Xuan, Z. Li, F. Dai, Y. Li, D. Cheng, R. Li, et al.
Complete Resequencing of 40 Genomes Reveals Domestication Events and Genes in Silkworm (Bombyx)
Science,
October 16, 2009;
326(5951):
433 - 436.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
V. Maybeck and K. Roper
A Targeted Gain-of-Function Screen Identifies Genes Affecting Salivary Gland Morphogenesis/Tubulogenesis in Drosophila
Genetics,
February 1, 2009;
181(2):
543 - 565.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. Keskiaho, L. Kukkola, A. P. Page, A. D. Winter, J. Vuoristo, R. Sormunen, R. Nissi, P. Riihimaa, and J. Myllyharju
Characterization of a Novel Caenorhabditis elegans Prolyl 4-Hydroxylase with a Unique Substrate Specificity and Restricted Expression in the Pharynx and Excretory Duct
J. Biol. Chem.,
April 18, 2008;
283(16):
10679 - 10689.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
K. E. Harris and S. K. Beckendorf
Different Wnt signals act through the Frizzled and RYK receptors during Drosophila salivary gland migration
Development,
June 1, 2007;
134(11):
2017 - 2025.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
C. Cao, Y. Liu, and M. Lehmann
Fork head controls the timing and tissue selectivity of steroid-induced developmental cell death
J. Cell Biol.,
March 12, 2007;
176(6):
843 - 852.
[Abstract]
[Full Text]
[PDF]
|
 |
|
© The Company of Biologists Ltd 2006