ABC transporter genes, kasKLM, responsible for self-resistance of a kasugamycin producer strain.

Abstract

We previously reported that a 7.6-kb DNA fragment from Streptomyces kasugaensis M338-M1, a kasugamycin (KSM) producer, included KSM acetyltransferase gene (kac338) and some other genes possibly involved in KSM biosynthesis. As an extension of that study, a 10-kb SacI-KpnI DNA fragment, located approximately 5-15-kb upstream of kac33, was cloned and a 4.2-kb SacI-EcoRI fragment therefrom was sequenced, revealing one incomplete (designated ORF J) and three complete open reading frames (designated kasK, kasL and kasM). The coding frames of kasK, L and M overlap one another with terminator/initiator ATGA sequence. RT-PCR analysis of a DNA region including kasKLM indicated the presence of one transcript that is long enough to span the three genes. The kasK gene potentially encodes an ATP-binding protein of the ATP-binding cassette (ABC) transporter superfamily. Homology search for the deduced KasK protein shows similarity to other ABC transporters involved in self-resistance of a mithramycin and possibly doxorubicin producer strain. The kasL and kasM genes encode different integral membrane proteins, both having six putative transmembrane helices. An expression plasmid for kasKLM (pTV-KLM) was constructed and these genes were expressed in E. coli JM 109, which had been sensitive to KSM. The transformant acquired resistance to KSM, suggesting that KasK, L and M proteins as a set in S. kasugaensis M338-M1 pump out KSM to protect the producer from its toxic metabolite.

• Authors: S Ikeno, Y Yamane, Y Ohishi, N Kinoshita, M Hamada, K S Tsuchiya, M Hori
• Journal: The Journal of antibiotics (J Antibiot (Tokyo)) Vol. 53 Issue 4 Pg. 373-84 (Apr 2000) ISSN: 0021-8820 [Print] England
• PMID: 10866219 (Publication Type: Journal Article)

Chemical References

• ATP-Binding Cassette Transporters
• Aminoglycosides
• Anti-Bacterial Agents
• DNA, Bacterial
• beta-Galactosidase
• kasugamycin

Topics

• ATP-Binding Cassette Transporters (genetics)
• Amino Acid Sequence
• Aminoglycosides
• Anti-Bacterial Agents (biosynthesis)
• Base Sequence
• Cloning, Molecular (methods)
• DNA, Bacterial (genetics)
• Drug Resistance, Microbial
• Escherichia coli (genetics)
• Gene Expression
• Molecular Sequence Data
• Open Reading Frames
• Plasmids (genetics)
• Streptomyces (genetics)
• beta-Galactosidase (metabolism)