Date of Award


Document Type


Degree Name

Master of Arts (MA)



First Advisor

Dr. Tom Weber


The slime mold Dictyostelium mucoroides is an effective model for studying eukaryotic development because it exists as both unicellular and multicellular entities depending on the stage of their life cycle. Development is regulated by a number of proteins. During the transition from single amebas to a multicellular entity, developmentally regulated proteins appear. In the case of the microcysts, produced during sexual reproduction, proteins not only function in the formation of the cell walls, but also aid in the fusion of gametes, selective phagocytosis, cell to cell contact, and make up lysosomal enzymes. We have cloned a developmentally regulated gene whose sequence shows homology to the gene encoding the protein ubiquitin. Ubiquitin is known to act as a selective marker of proteins for degradation. In other organisms, ubiquitin is involved in the regulation of the cell cycles and controlling development. The isolated gene was used as a probe to determine the number of copies of this gene in the genome of D. mucoroides and any changes in ubiquitin messenger RNA during development. The results of the Southern blot analysis showed that in D. mucoroides there are two copies of the ubiquitin gene. These are arranged in one chromosome and 800bp from each other. The RNA analysis identified four bands that were identical in size and quantity for each stage of development examined in both the microcyst and sorocarp life cycles. The results therefore show that in D. mucoroides the ubiquitin gene is not developmentally regulated.


A Thesis Presented to the Department of Biology and the Faculty of the Graduate College University of Nebraska In Partial Fulfillment of the Requirements for the Degree Master of Arts University of Nebraska at Omaha. Copyright 2000 Vincent Van Rothe.