Gradient fields and homeobox genes

Development ◽  
1991 ◽  
Vol 112 (3) ◽  
pp. 669-678 ◽  
Author(s):  
E.M. De Robertis ◽  
E.A. Morita ◽  
K.W. Cho
Keyword(s):  
Homeobox Genes ◽  
Homeodomain Proteins ◽  
Gradient Fields ◽  
Vertebrate Embryos ◽  
Morphogenetic Gradient

We review here old experiments that defined the existence of morphogenetic gradient fields in vertebrate embryos. The rather abstract idea of cell fields of organ-forming potential has become less popular among modern developmental and molecular biologists. Results obtained with antibodies directed against homeodomain proteins suggest that gradient fields may indeed be visualized at the level of individual regulatory molecules in vertebrate embryos.

Regulation and function of homeodomain proteins in the embryonic and adult vascular systemsThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.

2007 ◽  
Vol 85 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Josette M. Douville ◽  
Jeffrey T. Wigle
Keyword(s):  
Transcription Factors ◽  
Target Genes ◽  
Vascular System ◽  
Homeobox Genes ◽  
Tube Formation ◽  
Binding Motif ◽  
Homeodomain Proteins ◽  
Downstream Target ◽  
Endothelial Tube Formation ◽  
And Function

During embryonic development, the cardiovascular system first forms and then gives rise to the lymphatic vascular system. Homeobox genes are essential for both the development of the blood and lymphatic vascular systems, as well as for their maintenance in the adult. These genes all encode proteins that are transcription factors that contain a well conserved DNA binding motif, the homeodomain. It is through the homeodomain that these transcription factors bind to the promoters of target genes and regulate their expression. Although many homeodomain proteins have been found to be expressed within the vascular systems, little is known about their downstream target genes. This review highlights recent advances made in the identification of novel genes downstream of the homeodomain proteins that are necessary for regulating vascular cellular processes such as proliferation, migration, and endothelial tube formation. Factors known to regulate the functions of vascular cells via modulating the expression of homeobox genes will be discussed. We will also review current methods used to identify and characterize downstream target genes of homeodomain proteins.

scholarly journals A regulatory cascade of three homeobox genes, ceh-10, ttx-3 and ceh-23, controls cell fate specification of a defined interneuron class in C. elegans

Development ◽  
2001 ◽  
Vol 128 (11) ◽  
pp. 1951-1969 ◽  
Author(s):  
Zeynep Altun-Gultekin ◽  
Yoshiki Andachi ◽  
Ephraim L. Tsalik ◽  
David Pilgrim ◽  
Yuji Kohara ◽  
...  
Keyword(s):  
Nervous System ◽  
Cell Fate ◽  
Homeobox Genes ◽  
Homeobox Gene ◽  
Homeodomain Proteins ◽  
Differentiation Markers ◽  
Regulatory Relationship ◽  
C Elegans ◽  
Regulatory Cascade ◽  
The Individual

The development of the nervous system requires the coordinated activity of a variety of regulatory factors that define the individual properties of specific neuronal subtypes. We report a regulatory cascade composed of three homeodomain proteins that act to define the properties of a specific interneuron class in the nematode C. elegans. We describe a set of differentiation markers characteristic for the AIY interneuron class and show that the ceh-10 paired-type and ttx-3 LIM-type homeobox genes function to regulate all known subtype-specific features of the AIY interneurons. In contrast, the acquisition of several pan-neuronal features is unaffected in ceh-10 and ttx-3 mutants, suggesting that the activity of these homeobox genes separates pan-neuronal from subtype-specific differentiation programs. The LIM homeobox gene ttx-3 appears to play a central role in regulation of AIY differentiation. Not only are all AIY subtype characteristics lost in ttx-3 mutants, but ectopic misexpression of ttx-3 is also sufficient to induce AIY-like features in a restricted set of neurons. One of the targets of ceh-10 and ttx-3 is a novel type of homeobox gene, ceh-23. We show that ceh-23 is not required for the initial adoption of AIY differentiation characteristics, but instead is required to maintain the expression of one defined AIY differentiation feature. Finally, we demonstrate that the regulatory relationship between ceh-10, ttx-3 and ceh-23 is only partially conserved in other neurons in the nervous system. Our findings illustrate the complexity of transcriptional regulation in the nervous system and provide an example for the intricate interdependence of transcription factor action.

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