Evidence that HetR protein is an unusual serine-type protease

Zhou, Ruanbao; Wei, Xingcheng; Jiang, Nan; Li, Huiguang; Dong, Yuqing; Hsi, Kuo-L.; Zhao, Jindong

doi:10.1073/pnas.95.9.4959

Cited by 97 publications

(106 citation statements)

References 29 publications

Supporting

Mentioning

102

Contrasting

Order By: Relevance

“…Our results are consistent with recent data indicating that HetR is likely to be the PatS receptor (15). HetR is a key activator of heterocyst development (5) that was previously shown to be positively autoregulated (2) and to have autoproteolytic activity (38). Zhao's laboratory has now shown that HetR forms a homodimer with DNA-binding activity and that this DNA-binding activity is inhibited in vitro by synthetic PatS pentapeptide (15).…”

supporting

confidence: 82%

patS Minigenes Inhibit Heterocyst Development of Anabaena sp. Strain PCC 7120

Duan

Lee

et al. 2004

J Bacteriol

View full text Add to dashboard Cite

The patS gene encodes a small peptide that is required for normal heterocyst pattern formation in the cyanobacterium Anabaena sp. strain PCC 7120. PatS is proposed to control the heterocyst pattern by lateral inhibition. patS minigenes were constructed and expressed by different developmentally regulated promoters to gain further insight into PatS signaling. patS minigenes patS4 to patS8 encode PatS C-terminal 4 (GSGR) to 8 (CDERGSGR) oligopeptides. When expressed by P petE , P patS , or P rbcL promoters, patS5 to patS8 inhibited heterocyst formation but patS4 did not. In contrast to the full-length patS gene, P hepA -patS5 failed to restore a wild-type pattern in a patS null mutant, indicating that PatS-5 cannot function in cell-to-cell signaling if it is expressed in proheterocysts. To establish the location of the PatS receptor, PatS-5 was confined within the cytoplasm as a gfp-patS5 fusion. The green fluorescent protein GFP-PatS-5 fusion protein inhibited heterocyst formation. Similarly, full-length PatS with a C-terminal hexahistidine tag inhibited heterocyst formation. These data indicate that the PatS receptor is located in the cytoplasm, which is consistent with recently published data indicating that HetR is a PatS target. We speculated that overexpression of other Anabaena strain PCC 7120 RGSGR-encoding genes might show heterocyst inhibition activity. In addition to patS and hetN, open reading frame (ORF) all3290 and an unannotated ORF, orf77, encode an RGSGR motif. Overexpression of all3290 and orf77 under the control of the petE promoter inhibited heterocyst formation, indicating that the RGSGR motif can inhibit heterocyst development in a variety of contexts.

show abstract

supporting

confidence: 82%

patS Minigenes Inhibit Heterocyst Development of Anabaena sp. Strain PCC 7120

Duan

Lee

et al. 2004

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…The gel was stained using a silver-staining kit (Bio-Rad, Hercules, CA). To determine the pI of the Pa-AMP-1, isoelectric focusing gel electrophoresis was performed according to the method of Zhou et al (1998). The gel was stained with Coomassie Brilliant Blue.…”

Section: Electrophoresismentioning

confidence: 99%

“…The antibodies were specific to Pa-AMP-1 and GFP. Immunoblotting after Tricine SDS-PAGE was performed using horseradish peroxidase-conjugated goat anti-rabbit IgG antibodies as secondary antibodies, as described in Zhou et al (1998). To detect Pa-AMP-1 secretion from the pokeweed seeds during germination, seeds were first incubated in water for 12 h at 28°C, and then transferred onto a PVDF membrane, which was wet first before being placed on top of four layers of Whatman filter paper in a Petri dish.…”

Section: Immunological Detection Of Pa-amp-1mentioning

confidence: 99%

Purification, Characterization, and Molecular Cloning of the Gene of a Seed-Specific Antimicrobial Protein from Pokeweed

Ying-Fang

Luo

et al. 2000

Plant Physiology

Self Cite

View full text Add to dashboard Cite

A small cysteine-rich protein with antimicrobial activity was isolated from pokeweed (Phytolacca americana) seeds and purified to homogeneity. The protein inhibits the growth of several filamentous fungi and gram-positive bacteria. The protein was highly basic, with a pI higher than 10. The entire amino acid sequence of the protein was determined to be homologous to antimicrobial protein (AMP) from Mirabilis jalapa. The cDNA encoding the P. americana AMP (Pa-AMP-1) and chromosomal DNA containing the gene were cloned and sequenced. The deduced amino acid sequence shows the presence of a signal peptide at the amino terminus, suggesting that the protein is synthesized as a preprotein and secreted outside the cells. The chromosomal gene shows the presence of an intron located within the region encoding the signal peptide. Southern hybridization showed that there was small gene family encoding Pa-AMP. Immunoblotting showed that Pa-AMP-1 was only present in seeds, and was absent in roots, leaves, and stems. The Pa-AMP-1 protein was secreted into the environment of the seeds during germination, and may create an inhibitory zone against soil-borne microorganisms. The disulfide bridges of Pa-AMP-1 were identified. The three-dimensional modeling of Pa-AMP-1 indicates that the protein has a small cystine-knot folding, a positive patch, and a hydrophobic patch.

show abstract

“…NtcA is required for development and function of mature heterocysts, and for the expression of nitrogen transport and assimilation systems as well as N 2 fixation (Herrero et al, 2001). HetR is a key regulator of heterocyst differentiation (Buikema & Haselkorn, 1991) and is an autoregulated serine-type protease that can degrade itself and possibly other proteins (Zhou et al, 1998). HetR shows enhanced induction within 1-2 h of nitrogen stepdown, and within 3?5 h hetR expression is clearly localized to spaced cells, presumably developing pro-heterocysts (Black et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Diurnal expression of hetR and diazocyte development in the filamentous non-heterocystous cyanobacterium Trichodesmium erythraeum

et al. 2003

View full text Add to dashboard Cite

The marine non-heterocystous cyanobacterium Trichodesmium fixes atmospheric N2 aerobically in light. In situ immunolocalization/light microscopy of NifH revealed that lighter, non-granulated cell regions observed correspond to the nitrogenase-containing diazocyte clusters in Trichodesmium IMS101. The number of diazocyte clusters per trichome varied from 0 to 4 depending on trichome length. The constant percentage of diazocytes (approx. 15 %) in cultured strains and five natural populations suggests a developmentally regulated differentiation process. Real-time RT-PCR showed that ntcA, encoding the global nitrogen regulator in cyanobacteria, and hetR, the key regulatory gene in heterocyst differentiation, are both constitutively expressed during a 12 h/12 h light/dark cycle. hetR in addition showed a distinct peak in the dark (close to midnight) while nifH expression commenced 6–8 h later. The expression of all three genes was negatively affected by addition of ammonia. Some early heterocyst differentiation genes were also identified in the genome of Trichodesmium. The data suggest that hetR and ntcA may be required for development and function of diazocytes in Trichodesmium.

show abstract

Evidence that HetR protein is an unusual serine-type protease

Cited by 97 publications

References 29 publications

patS Minigenes Inhibit Heterocyst Development of Anabaena sp. Strain PCC 7120

patS Minigenes Inhibit Heterocyst Development of Anabaena sp. Strain PCC 7120

Purification, Characterization, and Molecular Cloning of the Gene of a Seed-Specific Antimicrobial Protein from Pokeweed

Diurnal expression of hetR and diazocyte development in the filamentous non-heterocystous cyanobacterium Trichodesmium erythraeum

Contact Info

Product

Resources

About