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Genetic Hierarchies (genetic + hierarchy)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Complementation of melanocyte development in SOX10 mutant neural crest using lineage-directed gene transfer

DEVELOPMENTAL DYNAMICS, Issue 1 2004
Ling Hou
Abstract An in vitro gene complementation approach has been developed to dissect gene function and regulation in neural crest (NC) development and disease. The approach uses the avian RCAS virus to express genes in NC cells derived from transgenic mice expressing the RCAS receptor TVA, under the control of defined promoter elements. Constructs for creating TVA transgenic mice were developed using site-specific recombination GATEWAY (GW), compatible vectors that can also be used to facilitate analysis of genomic fragments for transcriptional regulatory elements. By using these GW vectors to facilitate cloning, transgenic mouse lines were generated that express TVA in SOX10-expressing NC stem cells under the control of the Pax3 promoter. The Pax3-tv-a transgene was bred onto a Sox10 -deficient background, and the feasibility of complementing genetic NC defects was demonstrated by infecting the Pax3-tv-a cells with an RCAS- Sox10 expression virus, thereby rescuing melanocyte development of Sox10 -deficient NC cells. This system will be useful for assessing genetic hierarchies in NC development. Developmental Dynamics 229:54,62, 2004. © 2003 Wiley-Liss, Inc. [source]

Masters change, slaves remain

BIOESSAYS, Issue 1 2003
Patricia Graham
Sex determination offers an opportunity to address many classic questions of developmental biology. In addition, because sex determination evolves rapidly, it offers an opportunity to investigate the evolution of genetic hierarchies. Sex determination in Drosophila melanogaster is controlled by the master regulatory gene, Sex lethal (Sxl). DmSxl controls the alternative splicing of a downstream gene, transformer (tra), which acts with tra2 to control alternative splicing of doublesex (dsx). DmSxl also controls its own splicing, creating an autoregulatory feedback loop that ensures expression of Sxl in females, but not males. A recent paper1 has shown that in the dipteran Ceratitis capitata later (downstream) steps in the regulatory hierarchy are conserved, while earlier (upstream) steps are not. Cctra is regulated by alternative splicing and apparently controls the alternative splicing of Ccdsx. However, Cctra is not regulated by CcSxl. Instead it appears to autoregulate in a manner similar to the autoregulation seen with DmSxl. BioEssays 25:1,4, 2003. © 2002 Wiley Periodicals, Inc. [source]

Bapx1 homeobox gene gain-of-function mice show preaxial polydactyly and activated Shh signaling in the developing limb

DEVELOPMENTAL DYNAMICS, Issue 9 2006
Carla Tribioli
Abstract To explore Bapx1 homeobox gene function in embryonic control of development, we employed a gain-of-function approach to complement our previous loss-of-function mutant analysis. We show that transgenic mice overexpressing Bapx1 are affected by skeletal defects including hindlimb preaxial polydactyly and tibial hypoplasia. Bapx1 overexpression generates limb anteroposterior patterning defects including induction of Shh signaling and ectopic activation of functions downstream of Shh signaling into the anterior region of the autopod. Moreover, Bapx1 overexpression stimulates formation of limb prechondrogenic condensations. We also show that Shh is reciprocally able to activate Bapx1 expression in mouse embryos as the orthologous hedgehog (hh) does with the bagpipe/Bapx1 gene in Drosophila. Our results indicate that Bapx1 can modulate appendicular skeletal formation, that the genetic hierarchy between Shh/hh and Bapx1/bagpipe has been conserved during evolution, and that in mouse embryos these two genes can influence one another in a genetically reciprocal manner. We conclude that it is reasonable to expect overexpression of Bapx1 in certain forms of polydactyly. Developmental Dynamics 235:2483,2492, 2006. © 2006 Wiley-Liss, Inc. [source]

Playing by pair-rules?

BIOESSAYS, Issue 5 2003
Gregory K. Davis
Although in Drosophila pair-rule genes play crucial roles in the genetic hierarchy that subdivides the embryo into segments, the extent to which pair-rule patterning is utilized by different arthropods and other segmented phyla is unknown. Recent data of Dearden et al.1 and Henry et al.,2 however, hint that a pair-rule mechanism might play a role in the segmentation process of basal arthropods and vertebrates. BioEssays 25:425,429, 2003. © 2003 Wiley Periodicals, Inc. [source]