Research Groups
Yeast Molecular Genetics
Research Interests and Description
Research Interests
Genome dynamics in yeast: DNA integration, aneuploidy and chromosomal translocation.
Description of Research
The YMG Group has pioneered the field of chromosomal translocations induced in vivo, by implementing the novel bridge-induced translocation (BIT) methodology to construct different mutants carrying ad hoc chromosome translocations at pre-defined DNA points, using the yeast S. cerevisiae as a cellular eukaryotic model system. A first, most important conclusion deriving from our observations is that a single translocation event leads to a successive cascade of molecular events eventually ensuing in genomic instability. Most of these events involve DNA recombination and repair through the dynamic resolutions of their DNA Holliday junctions, requiring the activity of two major factors: Rvb1 and Rvb2. Chromosome translocation is generating severe alterations at both genomic and transcriptomic levels when this occurs between two heterologous chromosomes. However, this effect is greatly diminished when BIT occurs between two homologous chromosomes, with the important result that during the translocation process, a loss of heterozygosity (LOH) is generated on one of the recombinant chromosomes, preventing duplication of the region between the two recombining loci. We now have evidence that such alterations can be dealt with by the cell in several different ways, and that alteration to genomic homeostasis is expressed at the ploidy level, with the de-regulation of the copy number of many chromosomes harboring genes involved in almost all the cellular functions.
In this area, the first complete proteomic analysis, based on the 2D gel electrophoretic technique coupled with MALDI-TOF mass-spectrometry analysis, provided us with a general view of the differential protein profile between parental and translocant strains. This study revealed the altered expression of at least 24 proteins involved in energy metabolism, stress response, cell cycle, amino acids and cell wall biosynthesis in the translocant strains.
We are currently defining the gene architect of the BIT system, concentrating on those genes that have influence in the various aspects of DNA recombination and repair, using the FUN staining that indicates the physiological status of the cell. Moreover, we have started to implement a topological approach to chromosome translocation, based upon 3-D structure analysis of the yeast genome. This should lead to more insight to genetic adaptation following gross chromosomal rearrangement, and serve as a model to further understand the cellular and molecular effects of chromosome translocation and its aetiology of neoplastic transformation in mammals. Finally, these results are important for the manipulation and stable maintenance of Yeast Artificial Chromosomes (YACs), the use of which is at the basis of modern genome manipulation technologies, like recombineering.
The Group also works on an applied project, BIO-ETHOS, to construct a microbial system for the efficient biodegradation of lignocellulose by Bacilli bacteria, followed by the fermentation of the hemi- and cellulose by genetically engineered yeast strains in which the necessary cellulases have been cloned. The aim of this project is to produce bio-ethanol from fine industrial wood waste.
Recent Publications
Arnak, R., Bruschi, C.V. 2011. New multiple antibiotic resistance shuttle vectors allow scalable, PCR- mediated DNA manipulation and zero background cloning. Plasmid In press
Arnak, R., Bruschi, C.V., Tosato, V. 2011. Yeast Artificial Chromosomes. In: Encyclopedia of Life Sciences. John Wiley & Sons, Ltd: Chichester http://www.els.net/ [DOI: 10.1002/9780470015902.a0000379.pub3]
Rossi, B., Noel, P., Bruschi, C.V. 2010. Different Aneuploidies Arise From the Same Bridge-induced Cchromosomal Translocation. Event in Saccharomyces cerevisiae. Genetics 186, 775-790 PubMed link
Tosato, V., Nicolini, C., Bruschi, C.V. 2009. DNA bridging of homologous chromosomes in yeast leads to near-reciprocal translocation and loss of heterozygosity by deletion. Chromosoma 118, 179-191 PubMed link
Nikitin, D., Tosato, V., Zavec, A.B., Bruschi, C.V. 2008. Cellular and molecular effects of non-reciprocal chromosome translocations in S. cerevisiae. PNAS 105, 9703-9708 PubMed link
Radovic, S., Rapisarda, V.A., Tosato, V., Bruschi, C.V. 2007. Functional and comparative characterization of Saccharomyces cerevisiae RVB1 and RVB2 genes with bacterial Ruv homologues. FEMS Yeast Res 7, 527-539 PubMed link
