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Función del factor LIM-HD Tailup en el notum de "Drosophila"
|Authors:||Navascués, Joaquín de|
Genética del desarrollo
|Publisher:||Universidad Autónoma de Madrid|
|Abstract:||[BACKGROUND] In Drosophila, the notum territory of the wing disc is specified
during the second larval instar. At this stage, notum formation depends on EGFR
signalling pathway in the proximal part of the disc. This EGFR activity allows the
growth of the notum primordium and activates the expression of the members of
the iroquois complex (Iro-C), which endow the cells of the notum anlage with notum
identity. Here we have characterized the function in this process of the LIM-HD gene
tailup (tup = islet). This gene has been categorized as a prepattern gene that antagonizes
formation of sensory bristles on the notum of Drosophila. This function apparently
relies on inhibitory physical interactions of the Tup LIM domains with both Chip and
Pnr, which are important activators of the expression of the proneural achaete-scute
[RESULTS] We show that tup is expressed from the early second instar on and that its activity is required during the specification of the notum territory. Absence of tup function causes cells of this anlage to upregulate different wing-hinge genes and to lose expression of some notum genes. Consistently, these cells differentiate hinge structures or modified notum cuticle. The LIM-HD cofactors Chip and Ssdp are also necessary for notum specification; cells in the notum that lack any of these cofactors may express wing-hinge markers and lose notum markers, or even give rise to adults bearing ectopic hinge structures. This suggests that Tup acts in this process in a complex with Chip and Ssdp. We have evaluated the relative capacity of tup and the Iro-C member araucan to impose a notum developmental fate on other territories. We find that overexpression of tup, together with araucan, a pronotum gene member of the Iro-C, synergistically reinforces the weak capacity of either gene overexpressed singly to induce ectopic notum-like development. We have analysed the effect of several signalling pathways on tup expression, and identified the Dpp pathway as a positive regulator, while those of Wg, EGFR, PVR and Hh have no direct role in tup regulation.
[CONCLUSION] Our data support a model in which the EGFR and Dpp signalling pathways, with their respective downstream genes Iro-C and tup, converge and cooperate to commit cells to the notum developmental fate.
|Description:||Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura 20-07-2007|
|Appears in Collections:||(CBM) Tesis|
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|Joaquín de Navascués Melero.pdf||43,01 MB||Adobe PDF|