Identification and Characterization of Cell Division Cycle Mutants Followed by the Cloning of the Gene Responsible for a Cdc Phenotype in the Budding Yeast Kluyveromyces lactis

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Cell division, mutants, mutation, genes, Kluyveromyces lactis


Biology | Cell and Developmental Biology | Genetics and Genomics


The cell cycle is a highly detailed process that must be carried out with extreme measures of coordination to ensure organism survival. Yeast is a model organism for study of the cell cycle for many different reasons. Studies have been done on the Saccharomyces cerevisiae yeast cell cycle by Leland Hartwell in the 1970's followed by Paul Nurse's study of S. pombe. Studying a different yeast species, such as K. lactis, could possibly uncover new genes essential to the cell cycle not found in Hartwell's or Nurse's studies due to the type of mutational analyses performed.

K. lactis, like S. cerevisiae, is a budding yeast. This budding nature is especially useful in studying the cell cycle in that cells in a particular phase of the cell cycle can be easily identified through visual screening. K. lactis is also a simple unicellular Eukaryotic organism. This makes it relatively easy study and very useful in that eukaryotic processes are somewhat conserved across species; more direct applications can be made to human and animal cellular processes.

A bank of over 600 temperature sensitive K. lactis mutants has been generated through the use of ultraviolet light and ethylmethane sulfonate as mutagens. A total of 141 of these strains have been screened for cell division cycle mutations; twelve strains have been phenotypically identified as having mutations in essential cell division cycle genes. All twelve Cdc mutants have single recessive ts mutations as determined by backcrossing. Tests to determine complementation groupings of these twelve mutants have also been performed. Thus far, two mutants have tentatively been placed into the same complementation group. Ten of the twelve mutants are known to have a temperature sensitive phenotype of one mutant has been identified. DNA sequence at the ends of the fragment revealed that the rescue may be due to homologue of the CDC14 gene previously identified in Saccharomyces cerevisiae.

Department 1 Awarding Honors Status


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