PUL ID

PUL0015

PubMed

28970222, Appl Environ Microbiol. 2017 Nov 16;83(23). pii: AEM.01279-17. doi: 10.1128/AEM.01279-17. Print 2017 Dec 1.

Characterization method

microarray

Genomic accession number

NC_009004.1

Nucelotide position range

1209752-1217592

Substrate

cellobiose

Loci

LLMG_RS06265-LLMG_RS06290

Species

Lactococcus lactis/1358

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1227 - 2309 (+) STP: STP|SIS No
- 3316 - 5703 (+) CAZyme: GH9 Yes
- 5684 - 6991 (+) TC: gnl|TC-DB|U5MFA1|4.A.3.2.9 Yes
- 7029 - 7841 (+) CDS No

PUL ID

PUL0015

PubMed

28970222, Appl Environ Microbiol. 2017 Nov 16;83(23). pii: AEM.01279-17. doi: 10.1128/AEM.01279-17. Print 2017 Dec 1.

Title

Disruption of a Transcriptional Repressor by an Insertion Sequence Element Integration Leads to Activation of a Novel Silent Cellobiose Transporter in Lactococcus lactis MG1363.

Author

Solopova A, Kok J, Kuipers OP

Abstract

Lactococcus lactis subsp. cremoris strains typically carry many dairy niche-specific adaptations. During adaptation to the milk environment these former plant strains have acquired various pseudogenes and insertion sequence elements indicative of ongoing genome decay and frequent transposition events in their genomes. Here we describe the reactivation of a silenced plant sugar utilization cluster in an L. lactis MG1363 derivative lacking the two main cellobiose transporters, PtcBA-CelB and PtcBAC, upon applying selection pressure to utilize cellobiose. A disruption of the transcriptional repressor gene llmg_1239 by an insertion sequence (IS) element allows expression of the otherwise silent novel cellobiose transporter Llmg_1244 and leads to growth of mutant strains on cellobiose. Llmg_1239 was labeled CclR, for cellobiose cluster repressor.IMPORTANCE Insertion sequences (ISs) play an important role in the evolution of lactococci and other bacteria. They facilitate DNA rearrangements and are responsible for creation of new genetic variants with selective advantages under certain environmental conditions. L. lactis MG1363 possesses 71 copies in a total of 11 different types of IS elements. This study describes yet another example of an IS-mediated adaptive evolution. An integration of IS981 or IS905 into a gene coding for a transcriptional repressor led to activation of the repressed gene cluster coding for a plant sugar utilization pathway. The expression of the gene cluster allowed assembly of a novel cellobiose-specific transporter and led to cell growth on cellobiose.