This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Leszczynska, K. Articles by Ceglowski, P. Search for Related Content PubMed PubMed Citation Articles by Leszczynska, K. Articles by Ceglowski, P. Agricola Articles by Leszczynska, K. Articles by Ceglowski, P.

 Previous Article  |  Next Article 

Appl. Environ. Microbiol., 02 1995, 561-566, Vol 61, No. 2
Copyright © 1995, American Society for Microbiology

Cloning and molecular analysis of the dihydrofolate reductase gene from Lactococcus lactis

K Leszczynska, A Bolhuis, K Leenhouts, G Venema and P Ceglowski
Institute of Biochemistry and Biophysics, Warsaw, Poland.

The Lactococcus lactis gene encoding trimethoprim resistance has been cloned and expressed in Escherichia coli and Bacillus subtilis. Several lines of evidence indicate that the cloned gene encodes dihydrofolate reductase (DHFR). (i) It fully complements the fol "null" mutation in E. coli. (ii) Nucleotide sequencing of the cloned fragment revealed the presence of one open reading frame encoding a protein that shares homology with the family of bacterial DHFR enzymes. (iii) Overexpression of this open reading frame in E. coli resulted in the appearance in cell extracts of a protein of the expected size as well as in a dramatic increase of DHFR activity. In cell extracts, the DHFR activity was not inhibited by low trimethoprim concentration. By Northern (RNA) blotting and primer extension analyses, the size and the start point of the dhfr transcript, respectively, have been determined. Results of these experiments indicate that in L. lactis the dhfr gene represents part of a larger transcription unit.

This article has been cited by other articles:

• Sybesma, W., Starrenburg, M., Kleerebezem, M., Mierau, I., de Vos, W. M., Hugenholtz, J. (2003). Increased Production of Folate by Metabolic Engineering of Lactococcus lactis. Appl. Environ. Microbiol. 69: 3069-3076 [Abstract] [Full Text]