Homologous regulators, CnfR1 and CnfR2, activate expression of two distinct nitrogenase gene clusters in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.

Brenda S. Pratte; Teresa Thiel

doi:10.1111/mmi.13370

Homologous regulators, CnfR1 and CnfR2, activate expression of two distinct nitrogenase gene clusters in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.

Brenda S. Pratte
, Teresa Thiel

University of Missouri-St. Louis

Research output: Contribution to journal › Article › peer-review

Abstract

<div class="line" id="line-15"> The cyanobacterium  Anabaena variabilis  has two Mo&hyphen;nitrogenases that function under different environmental conditions in different cell types. The heterocyst&hyphen;specific nitrogenase encoded by the large  nif1  gene cluster and the similar  nif2  gene cluster that functions under anaerobic conditions in vegetative cells are under the control of the promoter for the first gene of each cluster,  nifB1  or  nifB2 respectively. Associated with each of these clusters is a putative regulatory gene called cnfR (patB) whose product has a  C&hyphen;terminal HTH domain and an N&hyphen;terminal ferredoxin&hyphen;like domain. CnfR1 activates  nifB1  expression in heterocysts, while CnfR2 activates  nifB2  expression. A  cnfR1  mutant was unable to make nitrogenase under aerobic conditions in heterocysts while the  cnfR2  mutant was unable to make nitrogenase under anaerobic conditions. Mutations in  cnfR1  and  cnfR2  reduced transcripts for the  nif1  and  nif2  genes respectively. The closely related cyanobacterium,  Anabaena  sp. PCC 7120 has the  nif1  system but lacks  nif2  . Expression of  nifB2  : lacZ  from  A. variabilis  in anaerobic vegetative cells of  Anabaena  sp. PCC 7120 depended on the presence of  cnfR2  . This suggests that CnfR2 is necessary and sufficient for activation of the  nifB2  promoter and that the CnfR1/CnfR2 family of proteins are the primary activators of nitrogenase gene expression in cyanobacteria. </div>

Original language	American English
Journal	Molecular Microbiology
Volume	100
DOIs	https://doi.org/10.1111/mmi.13370
State	Published - Jan 6 2016

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Genetics
Biology
Molecular Biology

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title = "Homologous regulators, CnfR1 and CnfR2, activate expression of two distinct nitrogenase gene clusters in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.",

abstract = " The cyanobacterium\  Anabaena variabilis\  has two Mo\&hyphen;nitrogenases that function under different environmental conditions in different cell types. The heterocyst\&hyphen;specific nitrogenase encoded by the large\  nif1\  gene cluster and the similar\  nif2\  gene cluster that functions under anaerobic conditions in vegetative cells are under the control of the promoter for the first gene of each cluster,\  nifB1\  or\  nifB2 respectively. Associated with each of these clusters is a putative regulatory gene called cnfR (patB) whose product has a\  C\&hyphen;terminal HTH domain and an N\&hyphen;terminal ferredoxin\&hyphen;like domain. CnfR1 activates\  nifB1\  expression in heterocysts, while CnfR2 activates\  nifB2\  expression. A\  cnfR1\  mutant was unable to make nitrogenase under aerobic conditions in heterocysts while the\  cnfR2\  mutant was unable to make nitrogenase under anaerobic conditions. Mutations in\  cnfR1\  and\  cnfR2\  reduced transcripts for the\  nif1\  and\  nif2\  genes respectively. The closely related cyanobacterium,\  Anabaena\  sp. PCC 7120 has the\  nif1\  system but lacks\  nif2\  . Expression of\  nifB2\  : lacZ\  from\  A. variabilis\  in anaerobic vegetative cells of\  Anabaena\  sp. PCC 7120 depended on the presence of\  cnfR2\  . This suggests that CnfR2 is necessary and sufficient for activation of the\  nifB2\  promoter and that the CnfR1/CnfR2 family of proteins are the primary activators of nitrogenase gene expression in cyanobacteria. ",

author = "Pratte, \{Brenda S.\} and Teresa Thiel",

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year = "2016",

month = jan,

day = "6",

doi = "10.1111/mmi.13370",

language = "American English",

volume = "100",

journal = "Molecular Microbiology",

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TY - JOUR

T1 - Homologous regulators, CnfR1 and CnfR2, activate expression of two distinct nitrogenase gene clusters in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.

AU - Pratte, Brenda S.

AU - Thiel, Teresa

N1 - Enter your email address below. If your address has been previously registered, you will receive an email with instructions on how to reset your password. If you don't receive an email, you should register as a new user

PY - 2016/1/6

Y1 - 2016/1/6

N2 - The cyanobacterium  Anabaena variabilis  has two Mo&hyphen;nitrogenases that function under different environmental conditions in different cell types. The heterocyst&hyphen;specific nitrogenase encoded by the large  nif1  gene cluster and the similar  nif2  gene cluster that functions under anaerobic conditions in vegetative cells are under the control of the promoter for the first gene of each cluster,  nifB1  or  nifB2 respectively. Associated with each of these clusters is a putative regulatory gene called cnfR (patB) whose product has a  C&hyphen;terminal HTH domain and an N&hyphen;terminal ferredoxin&hyphen;like domain. CnfR1 activates  nifB1  expression in heterocysts, while CnfR2 activates  nifB2  expression. A  cnfR1  mutant was unable to make nitrogenase under aerobic conditions in heterocysts while the  cnfR2  mutant was unable to make nitrogenase under anaerobic conditions. Mutations in  cnfR1  and  cnfR2  reduced transcripts for the  nif1  and  nif2  genes respectively. The closely related cyanobacterium,  Anabaena  sp. PCC 7120 has the  nif1  system but lacks  nif2  . Expression of  nifB2  : lacZ  from  A. variabilis  in anaerobic vegetative cells of  Anabaena  sp. PCC 7120 depended on the presence of  cnfR2  . This suggests that CnfR2 is necessary and sufficient for activation of the  nifB2  promoter and that the CnfR1/CnfR2 family of proteins are the primary activators of nitrogenase gene expression in cyanobacteria.

AB - The cyanobacterium  Anabaena variabilis  has two Mo&hyphen;nitrogenases that function under different environmental conditions in different cell types. The heterocyst&hyphen;specific nitrogenase encoded by the large  nif1  gene cluster and the similar  nif2  gene cluster that functions under anaerobic conditions in vegetative cells are under the control of the promoter for the first gene of each cluster,  nifB1  or  nifB2 respectively. Associated with each of these clusters is a putative regulatory gene called cnfR (patB) whose product has a  C&hyphen;terminal HTH domain and an N&hyphen;terminal ferredoxin&hyphen;like domain. CnfR1 activates  nifB1  expression in heterocysts, while CnfR2 activates  nifB2  expression. A  cnfR1  mutant was unable to make nitrogenase under aerobic conditions in heterocysts while the  cnfR2  mutant was unable to make nitrogenase under anaerobic conditions. Mutations in  cnfR1  and  cnfR2  reduced transcripts for the  nif1  and  nif2  genes respectively. The closely related cyanobacterium,  Anabaena  sp. PCC 7120 has the  nif1  system but lacks  nif2  . Expression of  nifB2  : lacZ  from  A. variabilis  in anaerobic vegetative cells of  Anabaena  sp. PCC 7120 depended on the presence of  cnfR2  . This suggests that CnfR2 is necessary and sufficient for activation of the  nifB2  promoter and that the CnfR1/CnfR2 family of proteins are the primary activators of nitrogenase gene expression in cyanobacteria.

UR - http://onlinelibrary.wiley.com/doi/10.1111/mmi.13370/abstract

U2 - 10.1111/mmi.13370

DO - 10.1111/mmi.13370

M3 - Article

VL - 100

JO - Molecular Microbiology

JF - Molecular Microbiology

ER -

Homologous regulators, CnfR1 and CnfR2, activate expression of two distinct nitrogenase gene clusters in the filamentous cyanobacterium Anabaena variabilis ATCC 29413.

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