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K Hinata

Publications and source records attributed to K Hinata.

34 records · Page 2Linked to original sources
PubMed1997

Striking sequence similarity in inter- and intra-specific comparisons of class I SLG alleles from Brassica oleracea and Brassica campestris: implications for the evolution and recognition mechanism.

Self-incompatibility in Brassica is controlled by a single multi-allelic locus (S locus), which contains at least two highly polymorphic genes expressed in the stigma: an S glycoprotein gene (SLG) and an S receptor kinase gene (SRK). The putative ligand-binding domain of SRK exhibits high homology to the secretory protein SLG, and it is believed that SLG and SRK form an active receptor kinase complex with a self-pollen ligand, which leads to the rejection of self-pollen. Here, we report 31 novel SLG sequences of Brassica oleracea and Brassica campestris. Sequence comparisons of a large number of SLG alleles and SLG-related genes revealed the following points. (i) The striking sequence similarity observed in an inter-specific comparison (95.6% identity between SLG14 of B. oleracea and SLG25 of B. campestris in deduced amino acid sequence) suggests that SLG diversification predates speciation. (ii) A perfect match of the sequences in hypervariable regions, which are thought to determine S specificity in an intra-specific comparison (SLG8 and SLG46 of B. campestris) and the observation that the hypervariable regions of SLG and SRK of the same S haplotype were not necessarily highly similar suggests that SLG and SRK bind different sites of the pollen ligand and that they together determine S specificity. (iii) Comparison of the hypervariable regions of SLG alleles suggests that intragenic recombination, together with point mutations, has contributed to the generation of the high level of sequence variation in SLG alleles. Models for the evolution of SLG/SRK are presented.

Alleles↗
PubMed1997

Highly conserved 5'-flanking regions of two self-incompatibility genes, SLG9 and SRK9.

The nucleotide (nt) sequences of the 5'-flanking regions of two Brassica self-incompatibility genes, SLG9 and SRK9, were determined. Their sequences were highly conserved: a region spanning 1.9 kb in the 5'-flanking region was completely identical except for a 1319-bp segment in SLG9. These observations strongly suggest that SLG9 and SRK9 together with their promoter regions were involved in a gene duplication or conversion event which occurred before the 1319-bp SLG9-specific sequence was inserted in SLG9 or deleted in SRK9.

Base Sequence↗
PubMed1997

Three members of the S multigene family are linked to the S locus of Brassica.

Two self-incompatibility genes in Brassica, SLG and SRK (SLG encodes a glycoprotein; SRK encodes a receptor-like kinase), are included in the S multigene family. Products of members of the S multigene family have an SLG-like domain (S domain) in common, which may function as a receptor. In this study, three clustered members of the S multigene family, BcRK1, BcRL1 and BcSL1, were characterized. BcRK1 is a putative functional receptor kinase gene expressed in leaves, flower buds and stigmas, while BcRL1 and BcSL1 are considered to be pseudogenes because deletions causing frameshifts were identified in these sequences. Sequence and expression pattern of BcRK1 were most similar to those of the Arabidopsis receptor-like kinase gene ARK1, indicating that BcRK1 might have a function similar to that of ARK1, in processes such as cell expansion or plant growth. Interestingly, the region containing BcRK1, BcRL1 and BcSL1 is genetically linked to the S locus and the physical distance between SLG, SRK and the three S-related genes was estimated to be less than 610 kb. Thus the genes associated with self-incompatibility exist within a cluster of S-like genes in the genome of Brassica.

Amino Acid Sequence↗
PubMed1996

The SLGs corresponding to the same S24-haplotype are perfectly conserved in three different self-incompatible Brassica campestris L.

We have identified three strains of the same S24-haplotype in self-incompatible B. campestris L. Two of them, S-12j and 1-1j, have been derived from Japanese populations and one, 27-1t, from Turkish one. The cDNA clones of SLG24 (S24-locus glycoprotein), which linked to the S-locus, were isolated from each strain, and sequenced. Each clone isolated from S-12j, 1-1j and 27-1t, was designated as SLG24 (S-12j), SLG24 (1-1j) and SLG24 (27-1t), respectively. Their nucleotide sequences were completely identical in coding region, 5' non-coding region, and 3' non-coding region, though the position of the polyadenylation site was slightly different among the cDNA clones. This result suggests that the origin of S24-haplotype in these three strains might be common, and that the nucleotide sequences of SLG24 of the same S24-haplotype are completely conserved among different populations. The high conservation of the SLG24 nucleotide sequences is probably essential for the recognition of self or non-self of self-incompatibility in this S24-haplotype.

Amino Acid Sequence↗
PubMed1995

Evolutionary aspects of the S-related genes of the Brassica self-incompatibility system: synonymous and nonsynonymous base substitutions.

In the Brassicaceae, self-vs. nonself-recognition in self-incompatibility is controlled by sporophytic S-alleles. Haplotypes specifying both SRK (S-receptor kinase) and SLG (S-locus glycoprotein) are considered to play an important role in the recognition reactions. We compared the nucleotide sequences of SRK9(Bc) and SRK6(Bo). The number of nonsynonymous substitutions per site (Pn) was lower, constrained, in the kinase than the receptor domain, while the numbers of synonymous substitutions (Ps) in the two domains were largely comparable. Pairwise values for Ps and Pn were calculated among 17 operational taxonomic units, including eight SLGs, the receptor domains of two SRKs, four SRAs (S-related A) and three SRBs (S-related B), which have high homologies with each other. The values of Ps and Pn of SLG were mostly comparable to those of the receptor domain of SRK. Dendrograms constructed on the basis of Pn and Ps indicated that SRA differentiated first, followed by SRB. The differentiation of SLG alleles is one of prerequisite factors for the establishment of self-incompatibility, and the allelic differentiation has occurred more than tens of million years ago.

Alleles↗
PubMed1995

Tapetum-specific expression of the gene for an endo-beta-1,3-glucanase causes male sterility in transgenic tobacco.

A cDNA for a pathogenesis-related endo-beta-1,3-glucanase isolated from soybean, was fused to an anther tapetum-specific promoter (Osg6B promoter) isolated from rice and the resulting chimeric gene was introduced into tobacco. The Osg6B promoter became active in the anther tapetum during formation of tetrads and the tapetal glucanase activity in the transgenic plants caused in a significant reduction in the number of fertile pollen grains. Most of the pollen grains were aberrant in shape, lacked germinal apertures and aggregate of the pollen grains. Granules of beta-1,3-glucan, which have not previously been reported, were often observed to adhere to the surface of the pollen grains. Further observations revealed that the callose wall was almost absent in the pollen tetrads of transgenic plants. In wild-type plants, by contrast, the tetrads were surrounded by callose that was degraded soon after the tetrad stage to release free microspores. Thus, the introduced gene for endo-beta-1,3-endoglucanase under the control of the Osg6B promoter caused digestion of the callose wall at the beginning of the tetrad stage, a time that was just a little earlier than the time at which endogenous glucanase activity normal appears. These results demonstrate that premature dissolution of the callose wall in pollen tetrads causes male sterility and suggest that the time at which tapetally produced glucanase is activate is critical for the normal development of microspores.

Base Sequence↗
PubMed1995

The sequences of S-receptor kinases (SRK) involved in self-incompatibility and their homologies to S-locus glycoproteins of Brassica campestris.

S-Receptor kinase (SRK) is a kind of receptor protein kinase and has a receptor domain resembling S-locus glycoprotein (SLG). cDNAs encoding SRK8 and SRK12 were isolated respectively from S8 and S12 haplotypes of Brassica campestris. The SLG domains of SRKs were highly homologous to SLGs, suggesting that both SLG and SRK might bind the same ligands in recognition of self-pollen.

Amino Acid Sequence↗
PubMed1995

Molecular cloning of members of the S-multigene family in self-incompatible Brassica campestris L.

We isolated 12 groups of genomic clones that contained SLG-homologous regions from a genomic library constructed from an S9 homozygote of self-incompatible Brassica campestris. Both SLG9 and SRK9 genomic clones, which are located within the self-incompatibility (S) locus, were included in these groups. The promoter regions of SLG9 and SRK9 were completely identical for at least 200 bp upstream from their respective initiation codons (ATG). The five sequence elements (boxes I to V) that are conserved in the promoters of SLG and SRK genes were also found in the SLG9 and SRK9 clones. However, one conserved element (box III) unexpectedly lacked 7 of 11 bp, although box III has been considered necessary for expression in pistil. The other ten groups of genomic clones were classified into six SRK-like groups and four SLG-like groups. These results indicate that SLG, SRK, SLG-like, and SRK-like genes form a large S-multigene family in B. campestris.

Base Sequence↗
PubMed1994

NPK15, a tobacco protein-serine/threonine kinase with a single hydrophobic region near the amino-terminus.

A cDNA clone (cNPK15) was isolated from tobacco cells in suspension culture, which encodes a predicted protein kinase of 422 amino acids. The predicted NPK15 protein consists of a hydrophobic region near the amino-terminus, a linker domain and the catalytic domain of a protein-serine/threonine kinase in the carboxyl-half. NPK15 was not found to be closely related to any reported protein, but its putative catalytic domain shares some structural similarity with those of receptor-like protein kinases of plants, such as ZmPK1 from Zea mays and TMK1 from Arabidopsis, even though no receptor-like domain is found in NPK15. Recombinant NPK15 expressed in Escherichia coli as a fusion protein was found capable of autophosphorylation and of phosphorylation of the histone H1 protein on both serine and threonine residues. Upon overexpression of cNPK15 under control of the promoter of cauliflower mosaic virus 35S RNA in tobacco cells, into which it had been introduced by Agrobacterium-mediated transformation, the NPK15 gene acted as a "suicide" gene and blocked proliferation of the host cells. By contrast, such a suicide effect was not observed with the gene for a kinase-negative mutant protein in which the nucleotide sequence for the ATP-binding site had been mutated or with a mutant derivative encoding a protein in which the hydrophobic region had been deleted. Thus, the protein kinase activity of NPK15 and the hydrophobic region of the protein are responsible for the suicide effect. The NPK15 protein kinase seems to be associated with specific cellular functions. Southern blot analysis with cNPK15 as the probe detected several fragments in restriction digests of genomic DNAs from both tobacco and other members of the Solanaceae. This results suggests that NPK15-related genes constitute a small gene family in the genomes of Solanaceae.

Amino Acid Sequence↗
PubMed1994

Molecular characterization of rice genes specifically expressed in the anther tapetum.

In situ localization of mRNA was carried out on two cDNAs (Osc4 and Osc6) that had been isolated from rice anthers at the microspore stage. The mRNA corresponding to each cDNA was shown to be localized only in the tapetal cells of the rice immature anthers, but not in the microspores or the mature pollen. The corresponding genomic clone, Osg6B, was isolated, and its 5'-upstream region was found to regulate beta-glucuronidase expression in the tapetum of transgenic tobacco. A set of 5' deletions was also generated and a 1095 bp 5' region was revealed to be necessary for activation of the Osg6B promoter in transgenic tobacco.

Base Sequence↗
PubMed1994

A high degree of homology exists between the protein encoded by SLG and the S receptor domain encoded by SRK in self-incompatible Brassica campestris L.

The sporophytic self-incompatibility system in Brassica campestris is controlled by multiple alleles of a single locus, S. We isolated and characterized cDNA clones that correspond to genes for S-glycoprotein (SLG) and S-receptor kinase (SRK) from an S9-homozygous strain. An SRK9 fragment was amplified by the polymerase chain reaction (PCR) by use of primers that corresponded to regions of the gene for the extracellular receptor domain (S-domain) and the kinase domain. The fragment was used as a probe to isolate an SRK9 cDNA clone from the cDNA library of stigmas of an S9-homozygote. An SLG9 cDNA clone was also isolated from the library by use of SLG8 cDNA as a probe. Restriction fragment length polymorphism (RFLP) linkage analysis of the F2 plants from an S8S9 hybrid demonstrated that the SRK and SLG genes were tightly linked to one another and were also linked to S-genotypes, as determined by pollination tests. The transcripts of SRK9 and SLG9 were detected in stigmas, but not in anthers or leaves. The cytoplasmic kinase domain encoded by SRK9 contained amino acid sequences that are conserved in serine/threonine kinases. The nucleotide sequence encoding the S-domain of SRK9 was 98.4% homologous to that of SLG9 at the nucleotide level. This observation suggests the existence of a mechanism for maintaining a high degree of similarity between SLG and the region that encodes the S-domain of SRK.

Base Sequence↗
PubMed1994

The sequences of S-glycoproteins involved in self-incompatibility of Brassica campestris and their distribution among Brassicaceae.

S-Glycoproteins have been thought to play a role in the self-incompatibility in Brassica plants. Two cDNAs encoding S-glycoproteins were isolated from stigmas of two strains of Brassica campestris. Their amino acid sequences are highly homologous to each other. However, the numbers of the potential glycosylation sites are different, although most of them are conserved. In the middle part of the sequences, there are two supervariable regions which might contribute to the specificity of each S-glycoprotein. Genomic Southern analysis showed many bands hybridizing with cDNA of S-glycoproteins in various Brassica species including self-compatible species.

Amino Acid Sequence↗