Francis Davis

Retired, Associate Professor

Emeritus

Department of Microbiology and Cell Science University of Florida 
Ph.D. (1968) Department of Biochemistry, 
University of Tennessee Medical Units, Memphis 
Postdoctoral: (1968-1969) St. Jude Children's Research Hospital (1969-1971) Department of Zoology, University of California, Berkeley

Teaching Interest

PCB 3134, Eukaryotic Cell Structure and Function

Description of Research

General areas: Gene expression; gene organization; transcriptional and translational regulation; DNA restriction systems.

The research objective was to improve the potential for genetic and metabolic engineering of Zymomonas mobilis. Two projects were designed to contribute to achieving this objective. (i) The transformation efficiency of Z. mobilis is low due to restriction systems of the organism. To understand the Z. mobilis restriction modifications system, restriction endonucleases and DNA methyl transferases genes are cloned and characterized. The activities of the gene products were analyzed to determine the role of the restriction modification systems in the low transformation efficiency of Z. mobilis. Results of these studies were used to develop strains of Z. mobilis with an enhanced potential for genetic and metabolic engineering by carrying out appropriate gene knock outs. (ii) To facilitate the transfer of genes from E. coli and Z. mobilis, a two component shuttle vector system is being developed. OriV from RSF1010 is cloned into a pBR322-derived plasmid. Transfer of the RSF10101 replication genes into Z. mobilis allows replication of the pBR-based plasmid in both Z. mobilis and E. coli. The availability of a small plasmid vector that will replicate in both E. coli and Z. mobilis allows cloning and gene manipulation in E. coli and direct transfer back into Z. mobilis. The small size of the plasmid also will improve the transformation efficiency compared to the large vector currently used. The approaches developed for improving the transformation efficiency of Z. mobilis and the development of a small plasmid shuttle vector system may provide a model for solving similar problems of poor transformation efficiencies in other organisms.

Among the DNA methyl transferase genes identified in Z. mobilis is a CcrM-like adenine methyl transferase gene. CcrM is a cell-cycle regulating methyl transferase that which has been recently identified and shown to be required for viability in several alpha subdivision proteobacteria. The Z. mobilis CcrM is being studied to determine its activity and potential role in cell cycle regulation.

Top

Selected Publications

Zhou, Shengde, Davis, F. C. and Ingram,L. O. 2001. Gene Integration and Expression and Extracellular Secretion of Erwinia chrysanthemi Endoglucanase CelY (celY) and CelZ (celZ) in Ethanologenic Klebsiella oxytoca P2. Appl. Environ. Microbiol. 67:6-14.

Martinez, Alfredo, Sean W. York, Lorraine P. Yomano, Van L. Pineda, Francis C. Davis, John C.Shelton, and Lonnie O. Ingram. 1999. Biosynthetic burdenand plasmid burden limit expression of chromosomally integrated heterologous genes (pdc, adhB) in Escherichia coli.  Biotechnol.Prog. 15:891-897.

Zhou, S., L. P. Yomano, A. Z. Saleh, F. C. Davis, H. C. Aldrich and L. O.Ingram. 1999. Enhancing expression and secretion of Erwinia chrysamathemi endogluconase (celZ) in Escherichia coli B.  Appl. Environ.Microbiol . 65:2439-2445.

Lia, X., F.C. Davis, R.B. Hespell and L.O. Ingram. 1997. Cloning of Cellobiose Phophoenol pyruvate-Dependent Phosphotransferase Genes: Functional Expression in Recombinant Escherichia coli and Identification of a Putative Binding Region for Disaccharides. Appl. Environ. Microbiol.63 :355-363.

Davis, F.C., J.C. Shelton, and L.D. Ingham. 1992. Nucleotide sequence of a repeating unit from the Urechis caupo core histone gene tandemrepeat. DNA Sequence 2:247-256.

Davis, F.C. Fertilization and development in the Echiura in "Reproductive Biology of Invertebrates" (K.G. Adiyodi and R.G. Adiyodi, eds.) Vol. 4,Part A, Oxford and IBH Publ. Co., New Delhi (1989) pp. 349-381.

Ingham, L.D. and F.C. Davis. 1988. Cloning and characterization of acore histone gene tandem repeat in Urechis caupo. Mol. Cell Biol . 8:4425-4432.

Top