Riassunti dei progetti del corso di dottorato di ricerca in biologia molecolare e cellulare
Project leader: FABIO FORNARA (fabio.fornara@unimi.it)
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- The candidate will use these tools as basis for his/her PhD project that will follow this rationale.
- Project leader: CARMELA GISSI (carmela.gissi@unimi.it)
Project leader: FABIO FORNARA (fabio.fornara@unimi.it)Location: Department of Biosciences, University of Milan, ItalyRESEARCH PROJECT SUMMARYMolecular control of flowering in rice Rice is a tropical plant that flowers when exposed to short day lengths (SDs), typical of tropical regions. However, many varieties are known that can be grown in temperate areas of the world, including Mediterranean Europe. Upon perception of a favourable photoperiod, leaves express proteins belonging to the Phosphatidylethanolamine Binding family. Such proteins, encoded by Heading Date 3a (Hd3a) and Rice Flowering Locus T 1 (RFT1), act as mobile signals that move through the vascular system to the shoot apical meristem, where they induce profound developmental reprogramming of the stem cell population present at the apex. Our laboratory is interested in understanding the molecular mechanisms responsible for reprogramming a group of undifferentiated cells to become an inflorescence. To this aim, we generated transgenic rice plants that express Hd3a and RFT1 under the control of a meristem-specific and inducible promoter. With such a tool we are able to trigger developmental reprogramming, independently of the day length conditions in which plants are grown.The candidate will use these tools as basis for his/her PhD project that will follow this rationale.Monitoring flowering at the phenotypic level by measuring flowering time of induced and non-induced plants, and the robustness of the system. Monitoring induction at the molecular level, assaying expression of candidate genes, known to be targets regulated by Hd3a and RFT1 proteins. Sampling meristematic cells, including the stem cell population, of induced and non-induced plants to perform global transcript profiling of genes differentially expressed during reprogramming. Profiling will be performed through next generation sequencing technologies. Validate candidate genes by independent methods of expression analysis. Study relevant candidates in transgenic rice lines, silencing or ectopically expressing the genes of interest. Project leader: CARMELA GISSI (carmela.gissi@unimi.it)Location: Department of Biosciences, University of Milan, ItalyRESEARCH PROJECT SUMMARYEvolutionary dynamics of nuclear genes involved in replication and repair of the mitochondrial genome in fast-evolving chordates The mitochondrial genome (mtDNA) of Metazoa is the molecule of choice in animal phylogenetic reconstructions but isalso regarded as a model system for studying the processes governing the evolution of an entire genome (Gissi et al. 2008). As peculiarity, this genome is characterized by co-evolution with the nuclear genome, in fact the biogenesis and maintenance of mitochondria depends on tightly regulated interactions between the nuclear and mt genetic systems (Garesse and Vallejo 2001; Cannino et al. 2007). For example, the mtDNA of metazoans encodes only for some subunits of the respiratory complexes and for few components of the mt protein synthesis machinery, while the overwhelming majority of mt proteins are encoded by the nucleus, including those involved in replication, transcription and repair of the mtDNA as well as in the formation of the mt nucleoid. In general, we can expect that these nuclear-encoded mt proteins will evolve in different way depending on the details of the mtDNA organization and functionality in the different taxa, and then on the overall mtDNA evolutionary trends. At present, the mtDNA has been completely sequenced in more than 2000 metazoan species belonging to the most diverse phyla, from sponges to mammals. Interestingly, among Chordata, the mtDNA of vertebrates shows low evolutionary rate and almost frozen structural and compositional features, while the mtDNA of Tunicata, the sister taxon of vertebrates, is characterized by fast nucleotide substitution rate, hypervariability of the gene order (with genes nevertheless all located on the same strand), apparent absence of a major regulatory region for transcription and replication, and strong variability of base composition and asymmetry (Gissi et al. 2010; Rubinstein et al. 2013). The aim of this project is to study the evolutionary dynamics of the above-mentioned nuclear-encoded gene categories in representative of vertebrates and tunicates, and in amphioxus (the only representative of Cephalochordata), in order to predict which proteins and protein-regions are mainly responsible of the differences observed between Tunicata, Vertebrata and Cephalochordata in the mt genome organization and functionality. This study will also allow the candidate to participate to new genome and transcriptome projects of tunicate species.
Cannino G, Di Liegro CM, Rinaldi AM (2007) Nuclear-mitochondrial interaction. Mitochondrion. 7: 359-366. Epub 2007 Aug 2002. Garesse R, Vallejo CG (2001) Animal mitochondrial biogenesis and function: a regulatory cross-talk between two genomes. Gene. 263: 1-16. Gissi C, Iannelli F, Pesole G (2008) Evolution of the mitochondrial genome of Metazoa as exemplified by comparison of congeneric species. Heredity 101: 301-320 Gissi C, Pesole G, Mastrototaro F, Iannelli F, Guida V, Griggio F (2010) Hypervariability of ascidian mitochondrial gene order: exposing the myth of deuterostome organelle genome stability. Mol Biol Evol. 27: 211-215. Rubinstein ND, Feldstein T, Shenkar N, Botero-Castro F, Griggio F, Mastrototaro F, Delsuc F, Douzery EJ, Gissi C, Huchon D (2013) Deep sequencing of mixed total DNA without barcodes allows efficient assembly of highly plastic ascidian mitochondrial genomes. Genome Biol Evol. 5: 1185-1199 Download 336.57 Kb. Share with your friends:
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