Characterization of devA, a gene required for the maturation of proheterocysts in the cyanobacterium Anabaena sp. strain PCC 7120.
Mutant M7, obtained by transposon mutagenesis of the cyanobacterium Anabaena sp. strain PCC 7120, is impaired in the development of mature heterocysts. Under aerobic conditions, the mutant is unable to fix N2 because of a deficiency of at least two components of the oxygen-protective mechanisms: a hemoprotein-coupled oxidative reaction and heterocyst-specific glycolipids. DNA contiguous with the inserted transposon was recovered from the mutant and sequenced. The transposon had inserted itself within a 732-bp open reading frame designated devA. The wild-type form of devA, obtained from a lambda-EMBL3 library of Anabaena sp. DNA, had the identical sequence. Directed mutagenesis of devA in the wild-type strain showed that the phenotype of the mutant was caused by insertion of the transposon. The wild-type form of devA on a shuttle vector complemented the mutation in M7. Expression of devA by whole filaments, monitored following nitrogen stepdown by using luxAB as the reporter, increased ca. eightfold during differentiation; the increase within differentiating cells was much greater. The deduced sequence of the DevA protein shows strong similarity to the ATP-binding subunit of binding protein-dependent transport systems. The product of devA may, therefore, be a component of a periplasmic permease that is required for the transition from a proheterocyst to a mature, nitrogen-fixing heterocyst.
Maldener
I
I
MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing 48824-1312.
Fiedler
G
G
Ernst
A
A
Fernández-Piñas
F
F
Wolk
C P
CP
D018528:ATP-Binding Cassette Transporters; D000251:Adenosine Triphosphatases / Q000235:genetics*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D017033:Anabaena / Q000145:classification / Q000166:cytology* / Q000235:genetics* / Q000254:growth & development; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D001692:Biological Transport / Q000235:genetics; D002454:Cell Differentiation; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009566:Nitrates / Q000378:metabolism; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; C091089:DevA protein, Anabaena; D009566:Nitrates; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases