Saturday, 23rd June 2018

Development and Regeneration

        Specification of Neuronal Identities in the Development of  the Drosophila Central Nervous System  




Fernando Jiménez Díaz-Benjumea




Research summary:

During the development of the Drosophila central nervous system neural stem cells, neuroblasts, divide asymmetrically to generate neurons and self-regenerate. In this process neuroblasts go through a series of temporal windows that define the fate of distinct neurons. These temporal windows are defined by the temporal expression of a set of transcription factors. Simultaneously, the expression of the HOX genes, along the anterior posterior axis of the embryo, generates diversity in the different segments. Our goal is to understand the mechanisms by which the HOX genes and the temporal factors interplay to define the combinatorial code of transcription factors that specify the fate of the different neurons. Our model systems are two sets of neurons characterized by the expression of neuropeptides Leucokinin and CCAP (Figure 1).

Expression pattern of Leukoquinin and CCAP neuropeptides in the Drosophila central nervous system.


At the end of the embryonic neurogenesis, neuroblasts either die by apoptosis or enter quiescence. Later in larval stages, neuroblasts resume proliferation and generate, in a second neurogenesis, the adult nervous system. Little is known about the mechanisms controlling entry into quiescence and maintenance of cell fate during quiescence (Figure 2).

Upon entering quiescence neuroblasts undergo marked changes in shape, here detected by immunostaning in stages 14, 15 and 16 of embryogenesis.












In abdominal segments only 3 out of 30 neuroblasts per hemisegment undergo quiescence, the rest die by apoptosis. We chose abdominal neuroblasts as model system to study first, how these two fates are genetically regulated, and secondly, which are the cellular changes involving the entry into a quiescence stage.


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