IDENTIFICATION OF MICROTUBULE-ORGANIZING CENTER (MTOC)-ASSOCIATED RNA MOLECULES AND EVALUATION OF THEIR FUNCTIONAL ROLE IN KEY CELLULAR PROCESSES

THE SPINDLE IS A BIPOLAR ARRAY OF MICROTUBULES TO WHICH THE CHROMOSOMES ATTACH AND THAT FACILITATES AN EQUAL DISTRIBUTION OF THE DUPLICATED GENETIC MATERIAL, ONCE REPLICATED, DURING CELL DIVISION. THE MICROTUBULES THAT CONSTITUTE THIS ARRAY EMANATE FROM STRUCTURES KNOWN AS MICROTUBULE-ORGANIZING CENTERS (MTOCS), WHICH LOCALIZE TO BOTH SPINDLE POLES. THE CELLS INITIALLY BEAR JUST ONE MTOC, WHICH IS DUPLICATED AT THE INITIAL STAGES OF THE CELL CYCLE. REMARKABLY, THERE ARE ONLY THREE OTHER CELLULAR ORGANELLES THAT ARE DUPLICATED DURING THE CELL CYCLE: THE NUCLEUS, THE MITOCHONDRIA AND THE PLASTIDS. INTERESTINGLY, ALL THESE OTHER ORGANELLES HAVE THEIR OWN RELATED GENETIC MATERIAL. THIS HAS LED TO THE PROPOSAL THAT MTOCS MUST ALSO COUNT WITH A SPECIFIC POOL OF ASSOCIATED NUCLEIC ACIDS. RECENT EVIDENCES SUPPORT THAT, IN THE CASE OF THE MTOCS, AND IN CONTRAST TO THE OTHER ORGANELLES DUPLICATED DURING THE CELL CYCLE, IT IS PROBABLY RNA AND NOT DNA MOLECULES THAT COULD BE INHERENTLY LINKED TO THESE STRUCTURES. DESPITE DATA SUSTAINING THE SPECIFIC ASSOCIATION OF RNAS TO MTOCS IS ACCUMULATING, THE FINAL CONFIRMATION OF THE EXISTENCE OF SUCH TRANSCRIPTS, THEIR SHARED CHARACTERISTICS AND THEIR PRECISE CELLULAR FUNCTIONS ARE FASCINATING OPEN QUESTIONS THAT WILL ONLY BE ANSWERED BY FURTHER IDENTIFYING NEW EXAMPLES OF SUCH MOLECULES. ACCORDINGLY, THE MAIN OBJECTIVE OF THIS PROJECT IS TO CARRY OUT THE FIRST GLOBAL SYSTEMATIC ANALYSIS TO IDENTIFY MTOC-ASSOCIATED RNAS IN THE BUDDING YEAST SACCHAROMYCES CEREVISIAE. THE CHARACTERIZATION OF THESE TRANSCRIPTS, THE MAIN MOLECULAR PATHWAYS AND CELLULAR FUNCTIONS IN WHICH THEY PARTICIPATE, AND THE EVALUATION OF THE POSSIBILITY THAT A SPECIFIC POOL OF RNA MOLECULES COULD ASYMMETRICALLY ASSOCIATE TO THE MTOCS IN THIS ORGANISM WILL ALLOW TO UNVEIL NEW MECHANISMS BY WHICH PIVOTAL PROCESSES SUCH AS CELL DIVISION, DIFFERENTIATION AND AGING ARE REGULATED.