title: Deletion of the Sm1 encoding motif in the lsm gene results in distinct changes in the transcriptome and enhanced swarming activity of Haloferax cells.
abstract: Members of the Sm protein family are important for the cellular RNA metabolism in all three domains of life. The family includes archaeal and eukaryotic Lsm proteins, eukaryotic Sm proteins and archaeal and bacterial Hfq proteins. While several studies concerning the bacterial and eukaryotic family members have been published, little is known about the archaeal Lsm proteins. Although structures for several archaeal Lsm proteins have been solved already more than ten years ago, we still do not know much about their biological function, however one can confidently propose that the archaeal Lsm proteins will also be involved in RNA metabolism. Therefore, we investigated this protein in the halophilic archaeon Haloferax volcanii. The Haloferax genome encodes a single Lsm protein, the lsm gene overlaps and is co-transcribed with the gene for the ribosomal L37.eR protein. Here, we show that the reading frame of the lsm gene contains a promoter which regulates expression of the overlapping rpl37R gene. This rpl37R specific promoter ensures high expression of the rpl37R gene in exponential growth phase. To investigate the biological function of the Lsm protein we generated a lsm deletion mutant that had the coding sequence for the Sm1 motif removed but still contained the internal promoter for the downstream rpl37R gene. The transcriptome of this deletion mutant was compared to the wild type transcriptome, revealing that several genes are down-regulated and many genes are up-regulated in the deletion strain. Northern blot analyses confirmed down-regulation of two genes. In addition, the deletion strain showed a gain of function in swarming, in congruence with the up-regulation of transcripts encoding proteins required for motility.
authors.affiliation: Biology II, Ulm University, 89069 Ulm, Germany.
authors.forename: Lisa-Katharina
authors.initials: LK
authors.lastname: Maier
authors.affiliation: Biology II, Ulm University, 89069 Ulm, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Benz
authors.affiliation: Biology II, Ulm University, 89069 Ulm, Germany.
authors.forename: Susan
authors.initials: S
authors.lastname: Fischer
authors.affiliation: Biology II, Ulm University, 89069 Ulm, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Alstetter
authors.affiliation: Institute of Molecular Biosciences, Goethe-University, 60438 Frankfurt, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Jaschinski
authors.affiliation: Institute of Medical Microbiology, Justus-Liebig University, 35392 Giessen, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Hilker
authors.affiliation: LOEWE Center for Synthetic Microbiology, Faculty of Biology, Philipps-University Marburg, 35032 Marburg, Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Becker
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Allers
authors.affiliation: Institute of Molecular Biosciences, Goethe-University, 60438 Frankfurt, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Soppa
authors.affiliation: Biology II, Ulm University, 89069 Ulm, Germany. Electronic address: anita.marchfelder@uni-ulm.de.
authors.forename: Anita
authors.initials: A
authors.lastname: Marchfelder
mesh_terms: D019843:Archaeal Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015152:Blotting, Northern; D015536:Down-Regulation; D017353:Gene Deletion; D019848:Gene Expression Regulation, Archaeal; D020745:Genome, Archaeal / Q000235:genetics; D019622:Haloferax volcanii / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D059372:Nucleotide Motifs / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D019642:RNA, Archaeal / Q000235:genetics / Q000378:metabolism; D012269:Ribosomal Proteins / Q000235:genetics; D059467:Transcriptome / Q000235:genetics*; D015854:Up-Regulation
chemical_list: D019843:Archaeal Proteins; D019642:RNA, Archaeal; D012269:Ribosomal Proteins
keywords: Archaea; Haloferax volcanii; Hfq; L37.eR; Lsm