Functional genomics and signalling in invasive growth of Schizosaccharomyces pombe

• Main Author: Braithwaite, Natalie Emma
• Published: University of Sussex 2011
• Subjects: 571.29; QD0415 Biochemistry
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554585

Schizosaccharomyces pombe is a unicellular organism which has been shown to undergo invasive filamentous growth under nitrogen deprived conditions. Through the completion of a genome-wide screen of S. pombe deletion mutants this invasive growth form has been separated into three stages: adhesion, invasion, filament formation. The filament formation of each deletion strain was analysed resulting in the classification of mutants into four morphologically aberrant groups: (Ia) strains that were unable to form filamentous protrusions, (Ib) strains that had thickened rope structures of their filamentous protrusions, (IIa) strains that had elongated cells in their filaments and (IIb) strains that had erratic structure of cells in their filaments. The screen also identified strains that exhibited altered levels of invasion efficiency. These were classified as hypo-invasive, poorly-invasive or hyper-invasive. Class Ia strains were selected for further analysis as they represent the tertiary stage of invasion, filament formation. To attempt to identify the signalling pathways involved in this stage, potential signalling compounds were added to growth media and any alteration in phenotypes were noted. cAMP, iron and calcineurin were all analysed for their roles in the tertiary stage of invasion. The non-invasive and poorly-invasive strains were also tested with these signalling compounds to attempt to elucidate their role in the secondary stage of invasive growth. Finally the role of spindle pole bodies (SPB) was analysed during filament formation. The SPB duplicates in late G1/S phase and in single cells the new SPB migrates to either cell end (new or old) in an un-biased pattern. Using GFP tagged SPB markers, the segregation pattern in filaments was analysed followed by creation of deletion mutant/SPB-GFP-tagged hybrids to attempt to elucidate the control of SPB segregation in filaments.