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Motoshi Kamada

Publications and source records attributed to Motoshi Kamada.

9 recordsLinked to original sources
PubMed2006

Anther-specific genes, which expressed through microsporogenesis, are temporally and spatially regulated in model legume, Lotus japonicus.

Pollen germination and pollen tube elongation are important for pollination and fertilization in higher plants. To date, several pollen-specific genes have been isolated and characterized. However, there is little information about the precise spatial and temporal expression pattern of pollen-specific genes in higher plants. In our previous study, we identified 132 anther-specific genes in the model legume Lotus japonicus by using cDNA microarray analysis, though their precise expression sites in the anther tissues were not determined. In this study, by using in situ hybridization experiments, we determined the spatial and temporal expression sites of 46 anther-specific genes (ca. 35%), which were derived from two groups, cluster I-a and cluster II-a, according to flower developmental stages. In the case of the genes grouped into cluster I-a, thirteen clones were characterized. The specific hybridized signals were varied among the clones, and were observed in tapetum cells, microspores, and anther walls at the early developmental stage of anther tissues. In the case of the genes classified into cluster II-a, we used thirty three different cDNA clones encoding primary and secondary metabolism-related proteins, cell wall reconstruction-related proteins, actin reorganization-related proteins, and sugar transport-related proteins, etc., as a probe. Interestingly, all genes in these thirty three clones examined were specifically expressed in the bicellular pollen grains, though the signal intensity was varied among clones. From the data of the cluster II-a genes, the mRNAs related to pollen germination and pollen tube elongation were specifically transcribed and preserved in mature pollen grains.

Gene Expression Regulation, Plant↗
PubMed2005

Shoot circumnutation and winding movements require gravisensing cells.

Circumnutation and winding in plants are universal growth movements that allow plants to survive despite their sessile nature. However, the detailed molecular mechanisms controlling these phenomena remain unclear. We previously found that a gravitropic mutant of Japanese morning glory (Pharbitis nil or Ipomoea nil), Shidare-asagao (weeping), is defective not only in circumnutation but also in the winding response. This phenotype is similar to that of the Arabidopsis SCARECROW (SCR) mutant. We therefore investigated whether morning glory SCR (PnSCR) is involved in the weeping phenotype. We found that one amino acid was inserted into the highly conserved VHIID motif in weeping-type PnSCR; this mutation caused abnormal endodermal differentiation. We introduced either the mutant or WT PnSCR into Arabidopsis scr mutants for complementation tests. PnSCR of the WT, but not of weeping, rescued the shoot gravitropism and circumnutation of scr. These results show that both the abnormal gravitropism and the circumnutation defect in weeping are attributable to a loss of PnSCR function. Thus, our data show that gravisensing endodermal cells are indispensable for shoot circumnutation and the winding response and that PnSCR is responsible for the abnormal phenotypes of weeping.

Amino Acid Sequence↗
PubMed2004

Identification and molecular characterization of novel anther-specific genes in Oryza sativa L. by using cDNA microarray.

The complicated genetic pathway regulates the developmental programs of male reproductive organ, anther tissues. To understand these molecular mechanisms, we performed cDNA microarray analyses and in situ hybridization to monitor gene expression patterns during anther development in rice. Microarray analysis of 4,304 cDNA clones revealed that the hybridization signal of 396 cDNA clones (271 non-redundant groups) increased more than six-fold in every stage of the anthers compared with that of leaves. Cluster analysis with the expression data showed that 259 cDNA clones (156 non redundant groups) were specifically or predominantly expressed in anther tissues and were regulated by developmental stage-specific manners in the anther tissues. These co-regulated genes would be important for development of functional anther tissues. Furthermore, we selected several clones for RNA in situ hybridization analysis. From these analyses, we found several novel genes that show temporal and spatial expression patterns during anther development in addition to anther-specific genes reported so far. These results indicate that the genes identified in this experiment are controlled by different programs and are specialized in their developmental and cell types.

Cluster Analysis↗
PubMed2004

Cloning and expression pattern of a novel microspore-specific gene encoding hypersensitive-induced response protein (LjHIR1) from the model legume, Lotus japonicus.

In order to understand the microspore and pollen development, recently, we have isolated a number of anther-specific genes in the model legume, Lotus japonicus. From these anther-specific genes, we identified one novel microspore-specific gene, LjImfb-c82. In order to determine the molecular characterization of LjImfb-c82, full-length cDNA clone was first isolated and sequenced. It encoded a protein of 286 amino acids (LjHIR1), which had sequence similarity to Hypersensitive-Induced Response like protein. LjHIR1 was specifically expressed in microspore on the in situ hybridization experiment. From the sequence similarity to prohibitin-domain protein, the LjHIR1 might be related to ion channel regulation in microspore development.

Amino Acid Sequence↗
PubMed2004

Space biology class as part of science education programs for high schools in Japan.

Declining incentives and scholastic abilities in science class has been concerned in Japan. The Ministry of Education, Culture, Sports, Science and Technology encourages schools to cooperate with research institutions to raise student's interest in natural sciences. The Science Partnership Program (SPP) and the Super Science High-School (SSH) are among such efforts. Our short SPP course consists of an introductory lecture on space biology in general and a brief laboratory practice on plant gravitropism. Space biology class is popular to students, despite of the absence of flight experiments. We suppose that students are delighted when they find that their own knowledge is not a mere theory, but has very practical applications. Space biology is suitable in science class, since it synthesizes mathematics, physics, chemistry and many other subjects that students might think uninteresting.

Biological Science Disciplines↗
PubMed2004

Gravity-regulated proteins of Arabidopsis and cucumber seedlings detected by 2-D electrophoresis.

Gravity exerts a profound influence on plant growth. Proteomics may be the most promising technique to identify the proteins that are induced, repressed, or post-transcriptionally modified during gravity response in plants. In this research, the model plant, Arabidopsis grown in stationary and clino-rotated condition for 7 to 10 days and cucumber plant with the unique gravimorphogenesis were used. Namely, cucurbit seedlings develop a peg on the transition zone between the hypocotyls and root. Cucumber seedlings grown in a horizontal position on the ground suppress the development of the peg (negatively-controlled) on the upper side of the transition zone in response to gravity. Then, we analyzed gravity-regulated proteins expression by two-dimensional (2-D) gel electrophoresis.

Arabidopsis↗
PubMed2003

Gravity-induced modification of auxin transport and distribution for peg formation in cucumber seedlings: possible roles for CS-AUX1 and CS-PIN1.

Cucurbit seedlings potentially develop a peg on each side of the transition zone between the hypocotyl and root. Seedlings grown in a horizontal position suppress the development of the peg on the upper side of the transition zone in response to gravity. It is suggested that this suppression occurs due to a reduction in auxin levels to below the threshold value. We show in this study that the free indole-3-acetic acid (IAA) content is low, while IAA conjugates are significantly more abundant in the upper side of the transition zone of gravistimulated seedlings, compared to the lower side. A transient increase in mRNA of the auxin-inducible gene, CS-IAA1, was observed in the excised transition zone. The result suggests that the transition zone is a source of auxin. Cucumber seedlings treated with auxin-transport inhibitors exhibited agravitropic growth and developed a peg on each side of the transition zone. Auxin-transport inhibitors additionally caused an increase in CS-IAA1 mRNA accumulation at the transition zone, indicating a rise in intracellular auxin concentrations due to a block of auxin efflux. To study the involvement of the auxin transport system in peg formation, we isolated the cDNAs of a putative auxin influx carrier, CS-AUX1, and putative efflux carrier, CS-PIN1, from cucumber (Cucumis sativus L.) plants. Both genes (CS-AUX1 in particular) were auxin-inducible. Accumulation of CS-AUX1 and CS-PIN1 mRNAs was observed in vascular tissue, cortex and epidermis of the transition zone. A reduced level of CS-AUX1 mRNA was observed in the upper side of the gravistimulated transition zone, compared with the lower side. It is therefore possible that a balance in the activities of auxin influx and efflux carriers controls intracellular auxin concentration at the transition zone, which results in lateral placement of a peg in cucumber seedlings.

Arabidopsis Proteins↗
PubMed2003

Isolation of auxin efflux carrier cDNA from cucumber.

Cucumber seedlings display not only gravitropism but also peg formation in response to gravity. Gravimorphogenesis is mediated by auxin distribution. As first step to reveal the mechanism that regulates auxin distribution by auxin efflux, we isolated five partial cDNAs of auxin efflux carriers by RT-PCR method. In addition, we isolated two full-length cDNAs (CsPIN2, CsPIN3) from a cucumber cDNA library. CsPIN2, AtPIN3, AtPIN4 and AtPIN7 fall within the same clade. CsPIN3, AtPIN1 and CsPIN1 fall within the same clade. CsPIN5, CsPIN6 and AtPIN2 fall within the same clade. Our phylogenetic analysis of PIN in cucumber and Arabidopsis indicates that cucumber may diversify CsPIN protein compared with AtPIN protein.

Arabidopsis Proteins↗