IAI FigSearch
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Woods, J. P.
Right arrow Articles by Goldman, W. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Woods, J. P.
Right arrow Articles by Goldman, W. E.

 Previous Article  |  Next Article 

Infect Immun, April 1998, p. 1697-1707, Vol. 66, No. 4
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Electrotransformation and Expression of Bacterial Genes Encoding Hygromycin Phosphotransferase and beta -Galactosidase in the Pathogenic Fungus Histoplasma capsulatum

Jon P. Woods,1,2,* Elizabeth L. Heinecke,1 and William E. Goldman2

Department of Medical Microbiology and Immunology, University of Wisconsin Medical School, Madison, Wisconsin 53706,1 and Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 631102

Received 3 September 1997/Returned for modification 22 October 1997/Accepted 19 January 1998

We developed an efficient electrotransformation system for the pathogenic fungus Histoplasma capsulatum and used it to examine the effects of features of the transforming DNA on transformation efficiency and fate of the transforming DNA and to demonstrate fungal expression of two recombinant Escherichia coli genes, hph and lacZ. Linearized DNA and plasmids containing Histoplasma telomeric sequences showed the greatest transformation efficiencies, while the plasmid vector had no significant effect, nor did the derivation of the selectable URA5 marker (native Histoplasma gene or a heterologous Podospora anserina gene). Electrotransformation resulted in more frequent multimerization, other modification, or possibly chromosomal integration of transforming telomeric plasmids when saturating amounts of DNA were used, but this effect was not observed with smaller amounts of transforming DNA. We developed another selection system using a hygromycin B resistance marker from plasmid pAN7-1, consisting of the E. coli hph gene flanked by Aspergillus nidulans promoter and terminator sequences. Much of the heterologous fungal sequences could be removed without compromising function in H. capsulatum, allowing construction of a substantially smaller effective marker fragment. Transformation efficiency increased when nonselective conditions were maintained for a time after electrotransformation before selection with the protein synthesis inhibitor hygromycin B was imposed. Finally, we constructed a readily detectable and quantifiable reporter gene by fusing Histoplasma URA5 with E. coli lacZ, resulting in expression of functional beta -galactosidase in H. capsulatum. Demonstration of expression of bacterial genes as effective selectable markers and reporters, together with a highly efficient electrotransformation system, provide valuable approaches for molecular genetic analysis and manipulation of H. capsulatum, which have proven useful for examination of targeted gene disruption, regulated gene expression, and potential virulence determinants in this fungus.

* Corresponding author. Mailing address: Department of Medical Microbiology and Immunology, 420 SMI, University of Wisconsin Medical School, 1300 University Ave., Madison, WI 53706-1532. Phone: (608) 265-6292. Fax: (608) 265-6132. E-mail: jpwoods{at}facstaff.wisc.edu.




This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 1998 by the American Society for Microbiology. All rights reserved.