Análisis de la función de las proteínas homeóticas en la formación de la genitalia de "Drosophila melanogaster"
Author
Foronda Alvaro, DavidAdvisor
Sánchez-Herrero, ErnestoEntity
UAM. Departamento de Biología MolecularDate
2007-07-12Subjects
Drosophilas-Genética-Tesis doctorales; Biología del desarrollo-Tesis doctorales; Biología y Biomedicina / BiologíaNote
Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura 12-07-2007Abstract
In most of the metazoan groups, the Hox genes determine segmental identity along the
anteroposterior axis of the organism. This is also the case of the fruitfly, Drosophila
melanogaster, the species in which these genes are best known. In Drosophila, the
Abdominal-B (Abd-B) Hox gene is required for the specification of the genital structures,
wich are derived from the genital disc. This gene encodes two different proteins, Abd-B
M and Abd-B R, required in abdominal segments A5-A8 and A9, respectively.
The embryonic genital disc, like the larval genital disc, is formed by cells from the
eighth (A8), ninth (A9) and tenth (A10) abdominal segments. We have found that the
Abd-B m transcript is expressed in the A8, the Abd-B r isoform in the A9 and Caudal in
the A10, as they are in the larval disk. In the mature disk, abdominal-A (abd-A) is coexpressed
with Abd-B m in a subdomain of the A8. Abd-B m is needed for the
development of A8 derivatives such as the external and internal female genitalia, the
latter also requiring abd-A. Abd-B r shapes male genitalia and female parovaria.
Although Abd-B r represses Abd-B m in the embryo, such regulation does not occur in
part of the male A9 or in a tiny region of the female A9: in the male A9, some of the
Abd-B r– clones that do not derepress Abd-B m behave as Abd-B m– r– clones do: they
activate Distal-less (Dll) and transform part of the genitalia into leg or antenna.
Similarly, in two lateral domains of the female A9 Abd-B r– clones do not derepress
Abd-B m and activate Dll. In the female A8, many Abd-B m– r– mutant clones
downregulate or eliminate abd-A expression. By contrast, although Abd-B m is the main
or only Abd-B transcript present in the female A8, Abd-B m– clones are not like Abd-B
m– r– clones, since Abd-B m– clones induced in this primordium do not alter Distal-less
or abd-A expression and transform the A8 segment into the A4 (instead of transforming
them into leg or antenna). We consistently observe that Abd-B m– clones in the female
A8 do not eliminate or reduce the amount of Abd-B protein (studied with an antibody
that recognizes both isoforms), suggesting that Abd-B r is activated there; this
relationship between Abd-B m and Abd-B r is the opposite to that observed in the
embryo. The relationship between Abd-B and abd-A in the female genital disc is also
opposite to that of the embryonic epidermis, and contravenes the rule that posteriorly
expressed Hox genes downregulate more anterior ones.
Finally, by functional substitution assays we have verifyed that Abd-B r is able to
partially rescue the lack of Abd-B m during the development of the genitalia, but abd-A
is not.
Files in this item
Google Scholar:Foronda Alvaro, David
This item appears in the following Collection(s)
Related items
Showing items related by title, author, creator and subject.
-
Análisis funcional de la proteína Abdominal-B y de los genes extradenticle y homothorax en Drosophila melanogaster
Rodríguez Curt, Jesús
2015-06-15 -
Análisis de los genes y mecanismos que median las funciones de las proteínas Spalt en el ala de Drosophila melanogaster
Martín Fernández, Mercedes
2016-04-22