Restoration of the wild-type locus in an RuBP carboxylase/oxygenase mutant of Synecbocystis PCC 6803 via targeted gene recombination

1992 ◽  
Vol 235 (2-3) ◽  
pp. 247-252 ◽  
Author(s):  
Doron Amichay ◽  
Meir Sheffer ◽  
Michael Gurevitz
Keyword(s):  
Gene Recombination ◽  
Wild Type ◽  
Rubp Carboxylase ◽  
Type Locus ◽  
Pcc 6803

ESCAPE FROM MATING-TYPE INCOMPATIBILITY IN BISEXUAL (A + a) NEUROSPORA HETEROKARYONS

1975 ◽  
Vol 17 (3) ◽  
pp. 441-449 ◽  
Author(s):  
A. M. DeLange ◽  
A. J. F. Griffiths
Keyword(s):  
Mating Type ◽  
Loss Of Function ◽  
Wild Type ◽  
Opposite Mating Type ◽  
Type Locus ◽  
Heterokaryon Incompatibility ◽  
Recessive Mutant ◽  
Type Rate ◽  
Wild Type Rate ◽  
Incompatibility Locus

In Neurospora crassa, strains of opposite mating type generally do not form stable heterokaryons because the mating type locus acts as a heterokaryon incompatibility locus. However, when one A and one a strain, having complementing auxotrophic mutants, are placed together on minimal medium, growth may occur, although the growth is generally slow. In this study, escape from such slow growth to that at a wild type or near-wild type rate was observed. The escaped cultures are stable heterokaryons, mostly having lost the mating type allele function from one component nucleus, so that the nuclear types are heterokaryon compatible. Either A or a mating type can be lost. This loss of function has been attributed to deletion since only one nuclear type could be recovered in all heterokaryons except one, but deletion spanning adjacent loci has been directly demonstrated in a minority of cases. Alternatively when one component strain is tol and the other tol+ (tol being a recessive mutant suppressing the heterokaryon incompatibility associated with mating type), escape may occur by the deletion or mutation of tol+, also resulting in heterokaryon compatibility. An induction mechanism for escape is speculated upon.

scholarly journals CORRIGENDUM

Genetics ◽  
1987 ◽  
Vol 115 (3) ◽  
pp. 579-579
Keyword(s):  
Sister Chromatid ◽  
Recombination Event ◽  
Linear Plasmid ◽  
Wild Type ◽  
Spore Viability ◽  
Yeast Plasmid ◽  
Type Locus ◽  
Sister Chromatids ◽  
Chromosome Ii ◽  
Meiosis I

ABSTRACT In the paper by Jules O'Rear and Jasper Rine (Genetics  113: 517-529; July, 1986) entitled "Precocious meiotic centromere separation of a novel yeast chromosome," the authors described a gene conversion event between a linear yeast plasmid carrying a LYS2 gene and a mutant lys2 gene at the wild-type locus on chromosome II. When these yeasts were mated to wild-type yeast and the resulting diploids sporulated, linked markers on the linear plasmid showed unusual segregation and poor spore viability was observed. On the basis of these observations, we proposed that the recombination event between the linear plasmid and chromosome II had split chromosome II into two fragments, one of which carried the normal centromere of chromosome II (fragment IIa) and the other, a telocentric fragment (fragment IIb), carried the centromere present on the linear plasmid. Separation of the chromosomes from these cells on OFAGE gels verified that chromosome II had been split into two fragments. Furthermore, we proposed that the sister chromatids of the telocentric fragment (fragment IIb) separated precociously in meiosis I when complete chromosome II and fragment IIa were present. In discussions with colleagues, an alternative explanation arose in which a recombination event between a sister chromatid of fragment IIa and a sister chromatid of chromosome II would result in each chromosome II chromatid being joined to a fragment IIa chromatid at CEN2. The two daughter cells of meiosis I would therefore each receive one chromatid of fragment IIa and one chromatid of chromosome II. Segregation of the two sister chromatids of fragment IIb to one pole in meiosis I without precocious centromere separation would result in the observed tetrad classes. To distinguish between these two mechanisms, a centromere-linked marker was introduced into the cross between the strain containing the two fragments of chromosome II and a wild-type strain. Tetrad analysis of the resulting diploid is consistent with the recombination model for the poor spore viability and inconsistent with precocious centromere separation. We thank Drs. Eric Lambie, Michael Lichten and Tom Petes for helpful discussions.

scholarly journals Role of Sigma Factors in Controlling Global Gene Expression in Light/Dark Transitions in the Cyanobacterium Synechocystis sp. Strain PCC 6803

2007 ◽  
Vol 189 (21) ◽  
pp. 7829-7840 ◽  
Author(s):  
Tina C. Summerfield ◽  
Louis A. Sherman
Keyword(s):  
Gene Expression ◽  
Global Gene Expression ◽  
Growth Conditions ◽  
Day Length ◽  
Regulation Of Transcription ◽  
Wild Type ◽  
Protein Levels ◽  
In The Wild ◽  
Altered Gene ◽  
Pcc 6803

ABSTRACT We report on differential gene expression in the cyanobacterium Synechocystis sp. strain PCC 6803 after light-dark transitions in wild-type, ΔsigB, and ΔsigD strains. We also studied the effect of day length in the presence of glucose on a ΔsigB ΔsigE mutant. Our results indicated that the absence of SigB or SigD predominately altered gene expression in the dark or in the light, respectively. In the light, approximately 350 genes displayed transcript levels in the ΔsigD strain that were different from those of the wild type, with over 200 of these up-regulated in the mutant. In the dark, removal of SigB altered more than 150 genes, and the levels of 136 of these were increased in the mutant compared to those in the wild type. The removal of both SigB and SigE had a major impact on gene expression under mixotrophic growth conditions and resulted in the inability of cells to grow in the presence of glucose with 8-h light and 16-h dark cycles. Our results indicated the importance of group II σ factors in the global regulation of transcription in this organism and are best explained by using the σ cycle paradigm with the stochastic release model described previously (R. A. Mooney, S. A. Darst, and R. Landick, Mol. Cell 20:335-345, 2005). We combined our results with the total protein levels of the σ factors in the light and dark as calculated previously (S. Imamura, S. Yoshihara, S. Nakano, N. Shiozaki, A. Yamada, K. Tanaka, H. Takahashi, M. Asayama, and M. Shirai, J. Mol. Biol. 325:857-872, 2003; S. Imamura, M. Asayama, H. Takahashi, K. Tanaka, H. Takahashi, and M. Shirai, FEBS Lett. 554:357-362, 2003). Thus, we concluded that the control of global transcription is based on the amount of the various σ factors present and able to bind RNA polymerase.

scholarly journals Whole genome re-sequencing of two ‘wild-type’ strains of the model cyanobacteriumSynechocystissp. PCC 6803

2014 ◽  
Vol 52 (1) ◽  
pp. 36-47 ◽  
Author(s):  
JN Morris ◽  
TS Crawford ◽  
A Jeffs ◽  
PA Stockwell ◽  
JJ Eaton-Rye ◽  
...  
Keyword(s):  
Whole Genome ◽  
Wild Type ◽  
Type Strains ◽  
Pcc 6803

scholarly journals Suppressor Mutations in the Study of Photosystem I Biogenesis: sll0088 Is a Previously Unidentified Gene Involved in Reaction Center Accumulation in Synechocystis sp. Strain PCC 6803

2003 ◽  
Vol 185 (13) ◽  
pp. 3878-3887 ◽  
Author(s):  
Jianping Yu ◽  
Gaozhong Shen ◽  
Tao Wang ◽  
Donald A. Bryant ◽  
John H. Golbeck ◽  
...  
Keyword(s):  
Photosystem I ◽  
Point Mutations ◽  
Kanamycin Resistance ◽  
Negative Regulator ◽  
Binding Motif ◽  
Wild Type ◽  
Photoautotrophic Growth ◽  
Suppressor Mutations ◽  
Mutant Strains ◽  
Pcc 6803

ABSTRACT In previous work, some members of our group isolated mutant strains of Synechocystis sp. strain PCC 6803 in which point mutations had been inserted into the psaC gene to alter the cysteine residues to the FA and FB iron-sulfur clusters in the PsaC subunit of photosystem I (J. P. Yu, I. R. Vassiliev, Y. S. Jung, J. H. Golbeck, and L. McIntosh, J. Biol. Chem. 272:8032-8039, 1997). These mutant strains did not grow photoautotrophically due to suppressed levels of chlorophyll a and photosystem I. In the results described here, we show that suppressor mutations produced strains that are capable of photoautotrophic growth at moderate light intensity (20 μmol m−2 s−1). Two separate suppressor strains of C14SPsaC, termed C14SPsaC-R62 and C14SPsaC-R18, were studied and found to have mutations in a previously uncharacterized open reading frame of the Synechocystis sp. strain PCC 6803 genome named sll0088. C14SPsaC-R62 was found to substitute Pro for Arg at residue 161 as the result of a G482→C change in sll0088, and C14SPsaC-R18 was found to have a three-amino-acid insertion of Gly-Tyr-Phe following Cys231 as the result of a TGGTTATTT duplication at T690 in sll0088. These suppressor strains showed near-wild-type levels of chlorophyll a and photosystem I, yet the serine oxygen ligand to FB was retained as shown by the retention of the S ≥ 3/2 spin state of the [4Fe-4S] cluster. The inactivation of sll0088 by insertion of a kanamycin resistance cartridge in the primary C14SPsaC mutant produced an engineered suppressor strain capable of photoautotrophic growth. There was no difference in psaC gene expression or in the amount of PsaC protein assembled in thylakoids between the wild type and an sll0088 deletion mutant. The sll0088 gene encodes a protein predicted to be a transcriptional regulator with sequence similarities to transcription factors in other prokaryotic and eukaryotic organisms, including Arabidopsis thaliana. The protein contains a typical helix-turn-helix DNA-binding motif and can be classified as a negative regulator by phylogenetic analysis. This suggests that the product of sll0088 has a role in regulating the biogenesis of photosystem I.

Photosystem II activity of wild type Synechocystis PCC 6803 and its mutants with different plastoquinone pool redox states

2016 ◽  
Vol 81 (8) ◽  
pp. 858-870
Author(s):  
O. V. Voloshina ◽  
Y. V. Bolychevtseva ◽  
F. I. Kuzminov ◽  
M. Y. Gorbunov ◽  
I. V. Elanskaya ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Wild Type ◽  
Synechocystis Pcc 6803 ◽  
Redox States ◽  
Plastoquinone Pool ◽  
Photosystem Ii Activity ◽  
Pcc 6803

scholarly journals Gene expression under low-oxygen conditions in the cyanobacterium Synechocystis sp. PCC 6803 demonstrates Hik31-dependent and -independent responses

Microbiology ◽  
2011 ◽  
Vol 157 (2) ◽  
pp. 301-312 ◽  
Author(s):  
Tina C. Summerfield ◽  
Sowmya Nagarajan ◽  
Louis A. Sherman
Keyword(s):  
Ribosomal Proteins ◽  
Chlorophyll Biosynthesis ◽  
Large Set ◽  
Wild Type ◽  
Low Oxygen ◽  
Knockout Mutant ◽  
Gene Encoding ◽  
Ps Ii ◽  
Oxygen Conditions ◽  
Pcc 6803

We have investigated the response of the cyanobacterium Synechocystis sp. PCC 6803 during growth at very low O2 concentration (bubbled with 99.9 % N2/0.1 % CO2). Significant transcriptional changes upon low-O2 incubation included upregulation of a cluster of genes that contained psbA1 and an operon that includes a gene encoding the two-component regulatory histidine kinase, Hik31. This regulatory cluster is of particular interest, since there are virtually identical copies on both the chromosome and plasmid pSYSX. We used a knockout mutant lacking the chromosomal copy of hik31 and studied differential transcription during the aerobic–low-O2 transition in this ΔHik31 strain and the wild-type. We observed two distinct responses to this transition, one Hik31 dependent, the other Hik31 independent. The Hik31-independent responses included the psbA1 induction and genes involved in chlorophyll biosynthesis. In addition, there were changes in a number of genes that may be involved in assembling or stabilizing photosystem (PS)II, and the hox operon and the LexA-like protein (Sll1626) were upregulated during low-O2 growth. This family of responses mostly focused on PSII and overall redox control. There was also a large set of genes that responded differently in the absence of the chromosomal Hik31. In the vast majority of these cases, Hik31 functioned as a repressor and transcription was enhanced when Hik31 was deleted. Genes in this category encoded both core and peripheral proteins for PSI and PSII, the main phycobilisome proteins, chaperones, the ATP synthase cluster and virtually all of the ribosomal proteins. These findings, coupled with the fact that ΔHik31 grew better than the wild-type under low-O2 conditions, suggested that Hik31 helps to regulate growth and overall cellular homeostasis. We detected changes in the transcription of other regulatory genes that may compensate for the loss of Hik31. We conclude that Hik31 regulates an important series of genes that relate to energy production and growth and that help to determine how Synechocystis responds to changes in O2 conditions.

scholarly journals The Malic Enzyme Is Required for Optimal Photoautotrophic Growth of Synechocystis sp. Strain PCC 6803 under Continuous Light but Not under a Diurnal Light Regimen

2004 ◽  
Vol 186 (23) ◽  
pp. 8144-8148 ◽  
Author(s):  
Terry M. Bricker ◽  
Shulu Zhang ◽  
Susan M. Laborde ◽  
Paul R. Mayer ◽  
Laurie K. Frankel ◽  
...  
Keyword(s):  
Malic Enzyme ◽  
Continuous Light ◽  
Light Conditions ◽  
Wild Type ◽  
Photoautotrophic Growth ◽  
Light Regimen ◽  
Synechocystis Sp ◽  
Pcc 6803

ABSTRACT A mutation was recovered in the slr0721 gene, which encodes the decarboxylating NADP+-dependent malic enzyme in the cyanobacterium Synechocystis sp. strain PCC 6803, yielding the mutant 3WEZ. Under continuous light, 3WEZ exhibits poor photoautotrophic growth while growing photoheterotrophically on glucose at rates nearly indistinguishable from wild-type rates. Interestingly, under diurnal light conditions (12 h of light and 12 h of dark), normal photoautotrophic growth of the mutant is completely restored.

scholarly journals ISOLATION AND PROPERTIES OF SELENOMETHIONINE-RESISTANT MUTANTS OF NEUROSPORA CRASSA

Genetics ◽  
1974 ◽  
Vol 77 (4) ◽  
pp. 627-638
Author(s):  
Gregory S Chen ◽  
Robert L Metzenberg
Keyword(s):  
Resistant Mutant ◽  
Heat Stability ◽  
Temperature Sensitive ◽  
Wild Type ◽  
High Concentration ◽  
Type Locus ◽  
Group I ◽  
In The Wild ◽  
Resistant Mutants ◽  
Adenosylmethionine Synthetase

ABSTRACT Mutants resistant to selenomethionine were isolated, and their properties studied. Mapping studies indicate that the mutation sites are located near the eth-1r locus in linkage group I, about ten map units away from the mating type locus. The sites of new mutation are either allelic to or very close to eth-1r. They are resistant not only to selenomethionine but also to ethionine, while the ethionine-resistant mutant, eth-1r, is sensitive to selenomethionine. The selenomethionine-resistant mutants are also temperature-sensitive mutants. However, they can grow at higher temperatures in medium containing 1 M glycerol.—It is very unlikely that the resistance is due to a change in the permeability of the membrane. Aryl sulfatase of se-metr mutants is not repressed by a high concentration of methionine (5 mM), although inorganic sulfate (2 mM) still can cause total repression. The γ-cystathionase levels of the mutants are normal, but the S-adenosylmethionine synthetase levels are only one-tenth of that observed in the wild-type strain. The heat-stability of this enzyme in the mutant is also different from that of the wild-type enzyme suggesting that the mutation might affect the structural gene of S-adenosylmethionine synthetase.

scholarly journals LINKAGE OF MUTATIONS AFFECTING MINUS FLAGELLAR MEMBRANE AGGLUTINABILITY TO THE mt  - MATING-TYPE LOCUS OF CHLAMYDOMONAS

Genetics ◽  
1981 ◽  
Vol 99 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Carol J Hwang ◽  
Brian C Monk ◽  
Ursula W Goodenough
Keyword(s):  
Uv Irradiation ◽  
Mating Type ◽  
Zygote Formation ◽  
Wild Type ◽  
Tetrad Analysis ◽  
Type Locus ◽  
Mating Type Locus ◽  
Flagellar Membrane ◽  
Mutant Strains

ABSTRACT Two independently isolated mutant strains, imp-10 and imp-12, were obtained by UV irradiation of wild-type mating-type minus (wt-). Each fails to agglutinate sexually with gametes of either mating type, but mating and zygote formation can be elicited by agglutinating either strain to wt+ gametes by means of anti-flagellar antiserum. Tetrad analysis of the resultant zygotes shows that both imp-10 and imp-12 are very closely linked to mt  -, with no recombinants observed. Diploid strains constructed between imp-10 or imp-12 and wt+ gametes are wt-, that is, they agglutinate and fuse like normal minus cells. Tetrad analysis of triploids from imp-10 diploid x wt+ haploid crosses shows that only imp-10 and wt+ products are recovered. A model is proposed to account for these results.

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