title: Analyses of both the alkB gene transcriptional start site and alkB promoter-inducing properties of Rhodococcus sp. strain BCP1 grown on n-alkanes.
abstract: Rhodococcus sp. strain BCP1, known for its capacity to grow on short-chain n-alkanes (C(2) to C(7)) and to cometabolize chlorinated solvents, was found to also utilize medium- and long-chain n-alkanes (C(12) to C(24)) as energy and carbon sources. To examine this feature in detail, a chromosomal region which includes the alkB gene cluster encoding a non-heme di-iron monooxygenase (alkB), two rubredoxins, and one rubredoxin reductase was cloned from the BCP1 genome. Furthermore, the activity of the alkB gene promoter (P(alkB)) was examined in the presence of gaseous, liquid, and solid n-alkanes along with intermediates of the putative n-alkane degradation pathway. A recombinant plasmid, pTP(alkB)LacZ, was constructed by inserting the lacZ gene downstream of P(alkB), and it was used to transform Rhodococcus sp. strain BCP1. Measurements of β-galactosidase activity showed that P(alkB) is induced by C(6) to C(22) n-alkanes. Conversely, C(2) to C(5) and >C(22) n-alkanes and alkenes, such as hexene, were not inducers of alkB expression. The effects on P(alkB) expression induced by alternative carbon sources along with putative products of n-hexane metabolism were also evaluated. This report highlights the great versatility of Rhodococcus sp. strain BCP1 and defines for the first time the alkB gene transcriptional start site and the alkB promoter-inducing capacities for substrates different from n-alkanes in a Rhodococcus strain.
authors.affiliation: Department of Biology, University of Bologna, Via Irnerio 42, I-40126 Bologna, Italy. martina.cappelletti2@unibo.it
authors.forename: M
authors.initials: M
authors.lastname: Cappelletti
authors.forename: S
authors.initials: S
authors.lastname: Fedi
authors.forename: D
authors.initials: D
authors.lastname: Frascari
authors.forename: H
authors.initials: H
authors.lastname: Ohtake
authors.forename: R J
authors.initials: RJ
authors.lastname: Turner
authors.forename: D
authors.initials: D
authors.lastname: Zannoni
mesh_terms: D000473:Alkanes / Q000378:metabolism*; D019677:Artificial Gene Fusion; D001426:Bacterial Proteins / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004734:Energy Metabolism; D015870:Gene Expression; D005798:Genes, Bacterial; D017930:Genes, Reporter; D008969:Molecular Sequence Data; D005810:Multigene Family; D010957:Plasmids; D011401:Promoter Regions, Genetic; D012240:Rhodococcus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D024363:Transcription Initiation Site; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
chemical_list: D000473:Alkanes; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D002244:Carbon; D001616:beta-Galactosidase