This thesis consists of work on the <I>wis1</I> pathway: the analysis of some of the upstream components and the isolation and characterisation of genes that lie downstream of <I>wis1</I>. The <I>mcs4, win1 </I>and <I>wis4</I> genes had already been shown to lie upstream of <I>wis1</I>. Strains were constructed with different combinations of mutations in these genes. <I>fbp1</I> transcription was assayed in these strains. An additive effect was seen in <I>win1 wis4</I> double mutants, suggesting that <I>win1</I> and<I> wis4</I> act in parallel. To identify functionally-related genes downstream of <I>wis1</I>, the stress sensitivity of <I>wis1Δ</I> cells was exploited. A screen for extragenic suppressing mutations was carried out. Several hundred heat resistant mutants were isolated. Some also presented the salt sensitivity and/or cell length defect of <I>wisΔ</I>. Twelve such <I>sow</I> (for suppressor of <I>wis1Δ</I>) mutants, each of which containing a single suppressing mutation, were analysed further. They fell into two linkage groups: <I>sow1</I> (nine strains) and <I>sow2</I> (three strains). When the <I>sow </I>mutations were crossed into a <I>wis1<SUP>+</SUP></I> background, both <I>sow1</I> and <I>sow2</I> were able to grow at temperatures above the usual range for <I>S. pombe</I>. In addition, <I>sow1</I> strains divide at a shorter length than wild type, indicating a mitotic advance, and <I>sow2</I> cells have a slightly aberrant morphology. To determine whether the <I>sow</I> mutations corresponded to any known genes, crosses were carried out between the <I>sow</I> mutants and mutants in the following genes: <I>wis1</I> pathway genes (<I>sty1, atf1</I>, <I>ppa1, ppa2 </I>and <I>ppe1</I>), cAMP pathway genes (<I>cyr1</I>, <I>pka1</I>) cell cycle regulation genes (<I>cdc2, cdc25, wee1, cdc13</I>), a heat shock protein (hsp90) gene (<I>swo1</I>) and a gene required for maintenance of the mitotic cell cycle (<I>pat1</I>).
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:660781 |
| Date | January 1998 |
| Creators | Prochnik, Simon Edward |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11284 |
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