Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvC
ABSTRACT Fusobacterium nucleatum is a key member of the human oral biofilm. It is also implicated in preterm birth and colorectal cancer. To facilitate basic studies of fusobacterial virulence, we describe here a versatile transposon mutagenesis procedure and a pilot screen for mutants defective in...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Society for Microbiology
2018-05-01
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| Series: | mBio |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/mBio.00360-18 |
| _version_ | 1819199710199545856 |
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| author | Chenggang Wu Abu Amar Mohamed Al Mamun Truc Thanh Luong Bo Hu Jianhua Gu Ju Huck Lee Melissa D’Amore Asis Das Hung Ton-That |
| author_facet | Chenggang Wu Abu Amar Mohamed Al Mamun Truc Thanh Luong Bo Hu Jianhua Gu Ju Huck Lee Melissa D’Amore Asis Das Hung Ton-That |
| author_sort | Chenggang Wu |
| collection | DOAJ |
| description | ABSTRACT Fusobacterium nucleatum is a key member of the human oral biofilm. It is also implicated in preterm birth and colorectal cancer. To facilitate basic studies of fusobacterial virulence, we describe here a versatile transposon mutagenesis procedure and a pilot screen for mutants defective in biofilm formation. Out of 10 independent biofilm-defective mutants isolated, the affected genes included the homologs of the Escherichia coli cell division proteins FtsX and EnvC, the electron transport protein RnfA, and four proteins with unknown functions. Next, a facile new gene deletion method demonstrated that nonpolar, in-frame deletion of ftsX or envC produces viable bacteria that are highly filamentous due to defective cell division. Transmission electron and cryo-electron microscopy revealed that the ΔftsX and ΔenvC mutant cells remain joined with apparent constriction, and scanning electron microscopy (EM) uncovered a smooth cell surface without the microfolds present in wild-type cells. FtsX and EnvC proteins interact with each other as well as a common set of interacting partners, many with unknown function. Last, biofilm development is altered when cell division is blocked by MinC overproduction; however, unlike the phenotypes of ΔftsX and ΔenvC mutants, a weakly adherent biofilm is formed, and the wild-type rugged cell surface is maintained. Therefore, FtsX and EnvC may perform novel functions in Fusobacterium cell biology. This is the first report of an unbiased approach to uncover genetic determinants of fusobacterial biofilm development. It points to an intriguing link among cytokinesis, cell surface dynamics, and biofilm formation, whose molecular underpinnings remain to be elucidated. IMPORTANCE Little is known about the virulence mechanisms and associated factors in F. nucleatum, due mainly to the lack of convenient genetic tools for this organism. We employed two efficient genetic strategies to identify F. nucleatum biofilm-defective mutants, revealing FtsX and EnvC among seven biofilm-associated factors. Electron microscopy established cell division defects of the ΔftsX and ΔenvC mutants, accompanied with a smooth cell surface, unlike the microfold, rugged appearance of wild-type bacteria. Proteomic studies demonstrated that FtsX and EnvC interact with each other as well as a set of common and unique interacting proteins, many with unknown functions. Importantly, blocking cell division by MinC overproduction led to formation of a weakly adherent biofilm, without alteration of the wild-type cell surface. Thus, this work links cell division and surface dynamics to biofilm development and lays a foundation for future genetic and biochemical investigations of basic cellular processes in this clinically significant pathogen. |
| first_indexed | 2024-12-23T03:20:40Z |
| format | Article |
| id | doaj.art-199fbf53faad457d9eba849871f7d978 |
| institution | Directory Open Access Journal |
| issn | 2150-7511 |
| language | English |
| last_indexed | 2024-12-23T03:20:40Z |
| publishDate | 2018-05-01 |
| publisher | American Society for Microbiology |
| record_format | Article |
| series | mBio |
| spelling | doaj.art-199fbf53faad457d9eba849871f7d9782022-12-21T18:02:00ZengAmerican Society for MicrobiologymBio2150-75112018-05-019210.1128/mBio.00360-18Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvCChenggang Wu0Abu Amar Mohamed Al Mamun1Truc Thanh Luong2Bo Hu3Jianhua Gu4Ju Huck Lee5Melissa D’Amore6Asis Das7Hung Ton-That8Department of Microbiology & Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas, USADepartment of Microbiology & Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas, USADepartment of Microbiology & Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas, USADepartment of Microbiology & Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas, USAHouston Methodist Hospital Research Institute, Houston, Texas, USAKorean Collection for Type Cultures, Korea Research Institute of Bioscience and Biotechnology, Jeongeup-si, Jeollabuk-do, Republic of KoreaDepartment of Microbiology & Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas, USADepartment of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, Connecticut, USADepartment of Microbiology & Molecular Genetics, University of Texas McGovern Medical School, Houston, Texas, USAABSTRACT Fusobacterium nucleatum is a key member of the human oral biofilm. It is also implicated in preterm birth and colorectal cancer. To facilitate basic studies of fusobacterial virulence, we describe here a versatile transposon mutagenesis procedure and a pilot screen for mutants defective in biofilm formation. Out of 10 independent biofilm-defective mutants isolated, the affected genes included the homologs of the Escherichia coli cell division proteins FtsX and EnvC, the electron transport protein RnfA, and four proteins with unknown functions. Next, a facile new gene deletion method demonstrated that nonpolar, in-frame deletion of ftsX or envC produces viable bacteria that are highly filamentous due to defective cell division. Transmission electron and cryo-electron microscopy revealed that the ΔftsX and ΔenvC mutant cells remain joined with apparent constriction, and scanning electron microscopy (EM) uncovered a smooth cell surface without the microfolds present in wild-type cells. FtsX and EnvC proteins interact with each other as well as a common set of interacting partners, many with unknown function. Last, biofilm development is altered when cell division is blocked by MinC overproduction; however, unlike the phenotypes of ΔftsX and ΔenvC mutants, a weakly adherent biofilm is formed, and the wild-type rugged cell surface is maintained. Therefore, FtsX and EnvC may perform novel functions in Fusobacterium cell biology. This is the first report of an unbiased approach to uncover genetic determinants of fusobacterial biofilm development. It points to an intriguing link among cytokinesis, cell surface dynamics, and biofilm formation, whose molecular underpinnings remain to be elucidated. IMPORTANCE Little is known about the virulence mechanisms and associated factors in F. nucleatum, due mainly to the lack of convenient genetic tools for this organism. We employed two efficient genetic strategies to identify F. nucleatum biofilm-defective mutants, revealing FtsX and EnvC among seven biofilm-associated factors. Electron microscopy established cell division defects of the ΔftsX and ΔenvC mutants, accompanied with a smooth cell surface, unlike the microfold, rugged appearance of wild-type bacteria. Proteomic studies demonstrated that FtsX and EnvC interact with each other as well as a set of common and unique interacting proteins, many with unknown functions. Importantly, blocking cell division by MinC overproduction led to formation of a weakly adherent biofilm, without alteration of the wild-type cell surface. Thus, this work links cell division and surface dynamics to biofilm development and lays a foundation for future genetic and biochemical investigations of basic cellular processes in this clinically significant pathogen.https://journals.asm.org/doi/10.1128/mBio.00360-18EnvCFtsXFusobacterium nucleatumallelic exchangebiofilmscell division |
| spellingShingle | Chenggang Wu Abu Amar Mohamed Al Mamun Truc Thanh Luong Bo Hu Jianhua Gu Ju Huck Lee Melissa D’Amore Asis Das Hung Ton-That Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvC mBio EnvC FtsX Fusobacterium nucleatum allelic exchange biofilms cell division |
| title | Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvC |
| title_full | Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvC |
| title_fullStr | Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvC |
| title_full_unstemmed | Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvC |
| title_short | Forward Genetic Dissection of Biofilm Development by <named-content content-type="genus-species">Fusobacterium nucleatum</named-content>: Novel Functions of Cell Division Proteins FtsX and EnvC |
| title_sort | forward genetic dissection of biofilm development by named content content type genus species fusobacterium nucleatum named content novel functions of cell division proteins ftsx and envc |
| topic | EnvC FtsX Fusobacterium nucleatum allelic exchange biofilms cell division |
| url | https://journals.asm.org/doi/10.1128/mBio.00360-18 |
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