Molecular mechanisms of monoaminergic neurons development in caenorhabditis elegans
- Autores: Angela Jimeno Martín
- Directores de la Tesis: Nuria Flames Bonilla (dir. tes.), María Isabel Fariñas Gómez (tut. tes.)
- Lectura: En la Universitat de València ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Antonio Miranda Vizuete (presid.), Inés Carrera (secret.), Maria Barrios (voc.)
- Programa de doctorado: Programa de Doctorado en Neurociencias por la Universitat de València (Estudi General)
- Materias:
- Enlaces
- Tesis en acceso abierto en: RODERIC
- Resumen
Specific cell identities are defined by the expression of selected transcriptomes that allow the cell to fulfill its distinctive functions. It is broadly stablished that transcriptomes are selected by specific combinations of transcription factors (TF) that bind selectively to the regulatory regions of the DNA, promoters and enhancers. In fact, it is the combinatorial and cooperative binding of transcription factors what promotes the expression of specific cell features. However, the mechanisms that allow TFs to identify regulatory regions remain poorly understood.
One of the niches that gathers more cell diversity is the nervous system, thus, this tissue becomes one of the best scenarios to study how distinct cell fates are acquired. In this Thesis we focus on monoaminergic system (MA), composed of distinct subpopulations of neurons that use biogenic amines as neurotransmitters, such as dopamine (DA), serotonin (5-HT) and adrenaline (A) and noradrenaline (NA), in vertebrates, or octopamine (OA) and tyramine (TA) in invertebrates. Monoaminergic system is conserved in all eumetazoans and regulates a plethora of complex behaviors, from locomotion to mood or appetite.
In this Thesis we took advantage of the phylogenetic conservation of monoaminergic neurons to use the nematode Caenorhabidtis elegans as a model system. C. elegans monoaminergic system is composed of four pairs of DA neurons (CEPV/D, ADE and PDE), four pairs (NSM, ADF, HSN and AIM) and a unilateral (RIH) serotonergic neurons; a pair of TA neurons (RIM) and another OA pair (RIC).
Using this nematode, our goal in this Thesis was to unravel which, among the 876 transcription factors present in C. elegans genome, play a key role in specification of monoaminergic neurons. To accomplish this aim, we optimized the RNAi strategy to perform an RNAi screen to knockdown the expression of all C. elegans TFs and look for defects in specific features of MA neurons, such us in the battery of genes required to synthesized the neurotransmitter. This strategy provided 91 TFs candidates involved in MA specification, we selected the ones that retrieved the most penetrant phenotypes and validate the results according to the MA subpopulation affected.
Our results showed that, for DA population, unc-62, vab-3 and unc-55 are essential in the regulatory complex that drives the specification of these neurons. Regarding 5-HT neurons, the combined action of lag-1 and hlh-14 promote the expression of ADF mature features and are determining in the behaviors exhibited by this neuron. Finally, the bZIP factor, zip-5, has been identified as the first TF known to be involved in the specification of RIC and RIM neurons.
To conclude, our work shed light into the transcriptional regulation of monoaminergic neurons, identifying key TFs that control the expression of identity genes of this population and that can be used to find functional orthologs in higher organisms that control monoaminergic specification.
