title: Mutation of the murC and murB Genes Impairs Heterocyst Differentiation in Anabaena sp. Strain PCC 7120.
abstract: To stabilize cellular integrity in the face of environmental perturbations, most bacteria, including cyanobacteria, synthesize and maintain a strong, flexible, three-dimensional peptidoglycan lattice. Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium capable of differentiating morphologically distinct nitrogen-fixing heterocyst cells in a periodic pattern. While heterocyst development has been shown to require proper peptidoglycan remodeling, the role of peptidoglycan synthesis has remained unclear. Here we report the identification of two peptidoglycan synthesis genes, murC (alr5065) and murB (alr5066), as required for heterocyst development. The murC and murB genes are predicted to encode a UDP-N-acetylmuramate:L-alanine ligase and a UDP-N-acetylenolpyruvoylglucosamine reductase, respectively, and we confirm enzymatic function through complementation of Escherichia coli strains deficient for these enzymes. Cells depleted of either murC or murB expression failed to differentiate heterocysts under normally inducing conditions and displayed decreased filament integrity. To identify the stage(s) of development affected by murC or murB depletion, the spatial distribution of expression of the patterning marker gene, patS, was examined. Whereas murB depletion did not affect the pattern of patS expression, murC depletion led to aberrant expression of patS in all cells of the filament. Finally, expression of gfp controlled by the region of DNA immediately upstream of murC was enriched in differentiating cells and was repressed by the transcription factor NtcA. Collectively, the data in this work provide evidence for a direct link between peptidoglycan synthesis and the maintenance of a biological pattern in a multicellular organism.
  
  
  OBJECTIVE
  Multicellular organisms that differentiate specialized cells must regulate morphological changes such that both cellular integrity and the dissemination of developmental signals are preserved. Here we show that the multicellular bacterium Anabaena, which differentiates a periodic pattern of specialized heterocyst cells, requires peptidoglycan synthesis by the murine ligase genes murC (alr5065) and murB (alr5066) for maintenance of patterned gene expression, filament integrity, and overall development. This work highlights the significant influence that intracellular structure and intercellular connections can have on the execution of a developmental program.
authors.affiliation: Department of Microbiology, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Videau
authors.affiliation: Department of Microbiology, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Orion S
authors.initials: OS
authors.lastname: Rivers
authors.affiliation: Department of Microbiology, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Blake
authors.initials: B
authors.lastname: Ushijima
authors.affiliation: Department of Microbiology, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Reid T
authors.initials: RT
authors.lastname: Oshiro
authors.affiliation: Department of Microbiology, University of Hawaii, Honolulu, Hawaii, USA.
authors.forename: Min Joo
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Corvallis, Oregon, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Philmus
authors.affiliation: Department of Biology, Illinois Wesleyan University, Bloomington, Illinois, USA lcozy@iwu.edu.
authors.forename: Loralyn M
authors.initials: LM
authors.lastname: Cozy
mesh_terms: D017033:Anabaena / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D010457:Peptidoglycan / Q000737:chemistry / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D010457:Peptidoglycan
references.citation: J Bacteriol. 1995 May;177(9):2387-95
references.pmid: 7730269
references.citation: MBio. 2015 Mar 17;6(2):e02109
references.pmid: 25784700
references.citation: J Bacteriol. 2001 Dec;183(23):6841-51
references.pmid: 11698373
references.citation: Proc Natl Acad Sci U S A. 2009 Nov 24;106(47):19884-8
references.pmid: 19897721
references.citation: J Bacteriol. 2015 Aug;197(16):2685-93
references.pmid: 26055115
references.citation: Appl Environ Microbiol. 2007 Feb;73(3):777-84
references.pmid: 17122399
references.citation: Microbiology. 2007 Feb;153(Pt 2):601-7
references.pmid: 17259632
references.citation: Methods Enzymol. 1988;167:747-54
references.pmid: 3148842
references.citation: Proc Natl Acad Sci U S A. 1991 Jun 15;88(12):5355-9
references.pmid: 11607193
references.citation: J Basic Microbiol. 2009 Feb;49(1):5-24
references.pmid: 19253332
references.citation: Trends Microbiol. 2011 Jun;19(6):278-85
references.pmid: 21458273
references.citation: Mol Microbiol. 2001 May;40(4):941-50
references.pmid: 11401701
references.citation: Cell Microbiol. 2011 Nov;13(11):1744-54
references.pmid: 21819512
references.citation: Biochemistry. 1997 Sep 30;36(39):11556-63
references.pmid: 9305945
references.citation: Nat Rev Microbiol. 2005 Aug;3(8):601-10
references.pmid: 16012516
references.citation: J Bacteriol. 2014 Dec;196(23):4026-35
references.pmid: 25201945
references.citation: J Bacteriol. 1994 Aug;176(15):4473-82
references.pmid: 7913926
references.citation: J Bacteriol. 2006 Mar;188(5):1808-16
references.pmid: 16484191
references.citation: MBio. 2015 Jun 30;6(4):e00376
references.pmid: 26126850
references.citation: Biochemistry. 2011 Nov 1;50(43):9212-24
references.pmid: 21942265
references.citation: Mol Microbiol. 2010 Aug;77(3):562-74
references.pmid: 20545862
references.citation: J Biol Chem. 2006 Jan 20;281(3):1714-24
references.pmid: 16236703
references.citation: Annu Rev Biochem. 2012;81:451-78
references.pmid: 22663080
references.citation: Microbiology. 2014 Sep;160(Pt 9):1874-81
references.pmid: 25061040
references.citation: J Bacteriol. 2003 Nov;185(22):6507-12
references.pmid: 14594822
references.citation: Mol Microbiol. 2014 Dec;94(6):1260-71
references.pmid: 25336355
references.citation: Proc Natl Acad Sci U S A. 2004 Apr 6;101(14):4848-53
references.pmid: 15051891
references.citation: EMBO J. 2008 May 7;27(9):1299-308
references.pmid: 18388860
references.citation: Comput Chem. 1999 Jun 15;23(3-4):341-64
references.pmid: 10404624
references.citation: J Bacteriol. 1995 Mar;177(6):1520-6
references.pmid: 7883709
references.citation: Trends Microbiol. 2012 Nov;20(11):548-57
references.pmid: 22898147
references.citation: Mol Microbiol. 2013 Jun;88(6):1093-105
references.pmid: 23663167
references.citation: BMC Genomics. 2014 Jan 13;15:22
references.pmid: 24417914
references.citation: J Bacteriol. 2000 Mar;182(5):1191-9
references.pmid: 10671437
references.citation: J Bacteriol. 1983 Apr;154(1):471-8
references.pmid: 6131881
references.citation: Mol Microbiol. 2011 Oct;82(1):87-98
references.pmid: 21819458
references.citation: Comput Chem. 2002 Jul;26(5):459-77
references.pmid: 12144176
references.citation: Cold Spring Harb Perspect Biol. 2010 Apr;2(4):a000315
references.pmid: 20452939
references.citation: Appl Environ Microbiol. 2010 Nov;76(22):7635-40
references.pmid: 20851961
references.citation: J Biol Chem. 1988 Jul 25;263(21):10088-95
references.pmid: 3292521
references.citation: Mol Microbiol. 2005 Jul;57(1):111-23
references.pmid: 15948953
references.citation: Science. 1998 Oct 30;282(5390):935-8
references.pmid: 9794762
references.citation: J Bacteriol. 1992 Oct;174(19):6025-32
references.pmid: 1328150
references.citation: Mol Microbiol. 2010 Mar;75(5):1159-70
references.pmid: 20487302
references.citation: Nucleic Acids Res. 2005 Jul 1;33(Web Server issue):W289-94
references.pmid: 15980472
references.citation: Arch Microbiol. 1977 Jul 26;114(1):35-41
references.pmid: 410379
references.citation: J Bacteriol. 1972 Nov;112(2):950-8
references.pmid: 4563986
references.citation: J Bacteriol. 2007 May;189(10):3884-90
references.pmid: 17369306
references.citation: Arch Microbiol. 2005 Dec;184(4):234-48
references.pmid: 16231162
references.citation: J Bacteriol. 2014 Mar;196(5):1113-21
references.pmid: 24375104
references.citation: Mol Microbiol. 2011 Mar;79(6):1655-69
references.pmid: 21244533
references.citation: Proc Natl Acad Sci U S A. 2001 Feb 27;98(5):2729-34
references.pmid: 11226308
references.citation: Mol Microbiol. 1993 Jul;9(1):77-84
references.pmid: 8412673
references.citation: Nucleic Acids Res. 1988 Aug 11;16(15):7351-67
references.pmid: 3045756
references.citation: J Bacteriol. 2001 Apr;183(8):2605-13
references.pmid: 11274121
references.citation: Proc Natl Acad Sci U S A. 2011 Dec 13;108(50):20130-5
references.pmid: 22135468
references.citation: Nat Prod Rep. 2001 Oct;18(5):503-19
references.pmid: 11699883
references.citation: Annu Rev Genet. 1996;30:59-78
references.pmid: 8982449
references.citation: J Bacteriol. 2015 Jan;197(2):362-70
references.pmid: 25384479
references.citation: J Bacteriol. 2012 Oct;194(19):5218-27
references.pmid: 22821973
references.citation: Nucleic Acids Res. 2005 Feb 07;33(3):816-24
references.pmid: 15699183