著者

Takashi Yasukawa Yasuyuki Nakahara Jun Hirai Yoshihiro H. Inoue

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.90, no.1, pp.11-20, 2015-02-01 (Released:2015-06-25)

参考文献数

62

被引用文献数

1 6

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Reactive oxygen species (ROS) generated during energy production processes are a major cause of oxidative DNA damage. A DNA glycosylase encoded by the Ogg1 gene removes oxidized guanine bases and is widely conserved. However, the biological role of the gene in individual organisms has not yet been characterized in Drosophila, which is a suitable model to study the influence of oxidative damage on senescence. Here, we performed a genetic analysis to confirm that Ogg1 plays an essential role in the removal of 8-oxo-guanines from nuclei. We first confirmed by quantitative real-time PCR that Ogg1 mRNA expression was reduced by 30–55% in Ogg1 mutants and in flies expressing inducible Ogg1 dsRNA compared to control flies. We then showed that additional accumulation of 8-oxo-guanines occurred in the nuclei of epithelial midgut cells after paraquat feeding in flies with downregulated Ogg1 expression. We confirmed that a transposon possessing the UAS sequence was integrated in the 5′-UTR of the Ogg1 alleles and that it is oriented in the same transcriptional direction as the gene. Using the Gal4/UAS system, which enables us to induce ectopic expression in Drosophila, we induced overexpression of Ogg1 by 40-fold. We observed a lower amount of 8-oxo-guanine in the midgut epithelial cells of adults overexpressing Ogg1. These genetic data strongly suggest that the Drosophila Ogg1 ortholog CG1795 plays an essential role in the suppression of 8-oxo-guanines, consistent with its role in other organisms. Although adult flies with reduced Ogg1 expression failed to show elevated sensitivity to paraquat, those with Ogg1 overexpression showed resistance to oxidative stress by paraquat feeding and had a significantly longer lifespan in normal feeding conditions. These observations are consistent with the hypothesis that oxidative DNA damage by ROS accumulation is a major contributor to senescence.

著者

執行 正義 田代 洋丞 宮崎 貞巳

出版者

日本遺伝学会

雑誌

The Japanese journal of genetics (ISSN:0021504X)

巻号頁・発行日

vol.69, no.4, pp.417-424, 1994-08-25

参考文献数

23

被引用文献数

14 21

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The chromosomal locations of glutamate oxaloacetate transaminase gene loci in Japanese bunching onion (<i>Allium fistulosum</i> L., 2<i>n</i>=2X= 16, FF) and shallot (<i>A. cepa</i> L. Aggregatum group, 2<i>n</i>=2X = l6, AA) were investigated using alien monosomic addition lines (2<i>n</i>=2X+1=17, FF+nA, AA+nF) and hypoallotriploid lines (2<i>n</i>=3X-1=23, AFF-nA, AAF-nF) between these two species. The gene locus <i>Got-2</i> was located on the homoeologous sub-telocentric chromosomes, 6F in <i>A. fistulosum</i> and 6A in <i>A. cepa</i> Aggregatum group. The gene locus <i>Got-1</i> was on the other chromosomes. The present results indicate that chromosomal locations of these gene loci, at least <i>Got-2</i>, were conservative both in <i>A. fistulosum</i> and <i>A. cepa</i> Aggregatum group during speciation and subsequent evolution.<br>

著者

Koichiro Tsunewaki Naoki Mori Shigeo Takumi

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.89, no.5, pp.195-202, 2014-10-01 (Released:2015-04-02)

参考文献数

19

被引用文献数

2

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In the course of reconstructing Aegilops caudata from its own genome (CC) and its plasmon, which had passed half a century in common wheat (genome AABBDD), we produced alloplasmic Ae. cylindrica (genome CCDD) with the plasmon of Ae. caudata. This line, designated (caudata)-CCDD, was found to express male sterility in its second substitution backcross generation (SB2) of (caudata)-AABBCCDD pollinated three times with the Ae. cylindrica pollen. We repeatedly backcrossed these SB2 plants with the Ae. cylindrica pollen until the SB5 generation, and SB5F2 progeny were produced by self-pollination of the SB5 plants. Thirteen morphological and physiological characters, including pollen and seed fertilities, of the (caudata)-CCDD SB5F2 were compared with those of the euplasmic Ae. cylindrica. The results indicated that the male sterility expressed by (caudata)-CCDD was due to genetic incompatibility between the Ae. cylindrica genome and Ae. caudata plasmon that did not affect any other characters of Ae. cylindrica. Also, we report that the genome integrity functions in keeping the univalent transmission rate high.

著者

Yoshiyuki Suzuki Yuki Kobayashi Masayuki Horie Keizo Tomonaga

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.89, no.3, pp.143-148, 2014-06-01 (Released:2014-12-04)

参考文献数

46

被引用文献数

1 12

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Endogenous bornavirus-like nucleoprotein (EBLN) elements are nucleotide sequences homologous to the bornavirus N gene that have been identified in animal genomes. EBLN elements are considered to have been generated through reverse transcription of bornavirus N mRNA, mainly with the aid of long interspersed element-1 (LINE-1). The genome of thirteen-lined ground squirrels (Ictidomys tridecemlineatus) contains an EBLN element, itEBLN, which is thought to have been integrated less than 8.5 million years ago (MYA). However, it was also reported that the LINE-1 activity on this lineage was lost 4-5 MYA. Here, molecular evolutionary analyses were conducted to gain insights into the integration time of itEBLN. In a phylogenetic analysis of bornavirus N and itEBLN, using an EBLN element from cape golden moles (Chrysochloris asiatica) (caEBLN) as the outgroup, the integration time of itEBLN appeared to be close to the time of the most recent common ancestor (MRCA) for bornavirus N. From an analysis of genomic sequences for bornavirus strains isolated at different time points, the time of the MRCA for bornavirus N was estimated to be < 0.3 MYA. These results suggest that the integration time of itEBLN was much later than the loss of LINE-1 activity, supporting the non-LINE-1-mediated integration of itEBLN.

著者

Shu Kondo

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.89, no.1, pp.3-8, 2014 (Released:2014-05-10)

参考文献数

41

被引用文献数

7 17

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Drosophila melanogaster has the longest history as a genetic model system and even in the present day remains the front runner in diverse fields of biology. However, lack of a convenient method to make specified modifications to endogenous genes has been a pain in the neck for many fly geneticists for decades. Synthetic nuclease technologies, especially the CRISPR/Cas9 system, hold great promise for a breakthrough. Synthetic nucleases are programmable nucleases that can be directed to cleave a specified sequence in the genome. Deleterious mutations can be efficiently induced by expression of a synthetic nuclease that targets a gene of interest. Precise modification of the target site, such as a reporter gene knock-in, is also possible by simultaneous delivery of a synthetic nuclease and a targeting vector. Here I summarize recent advances in synthetic nuclease technologies and discuss their possible applications to Drosophila genetics.

著者

Yusaku Yasuno Yoshihiro H. Inoue Masa-Toshi Yamamoto

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.88, no.2, pp.113-126, 2013 (Released:2013-07-06)

参考文献数

40

被引用文献数

3

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Sex ratio distortion, which is commonly abbreviated as sex-ratio, has been studied in many Drosophila species, but the mechanism remains largely unknown. Here, we report on the sex-ratio mutant of D. simulans named excess of females (exf). The third chromosomal recessive mutation results in a sex ratio of approximately 0.2 or less (males/total). Cytological observation demonstrated that meiosis appeared to be completed normally, but that most Y chromosome-bearing nuclei failed to elongate during spermiogenesis, as revealed by fluorescence in situ hybridization using sex chromosome-specific probes. These aberrant nuclei contained membranous inclusions as revealed by electron microscopic analysis. Most of the aberrant exf spermatids failed to individualize and mature, suggesting that a later stage of spermiogenesis is involved in prevention of production of sperm with abnormal morphology. On the one hand, in exf seminal vesicles, sperm nuclei with a length of 5–8.5 μm were occasionally observed, in addition to those with wild-type sperm dimensions, that is, a length of approximately 10 μm. Thus, spermatids with less severe nuclear defects can escape elimination and be released into the seminal vesicles as mature sperm. Furthermore, we constructed His2AvD-GFP and ProtamineB-eGFP transgenic lines in D. simulans, and examined the processes involved in replacement of chromatin proteins over a time course, according to nuclear morphology. We found that both normal and abnormal sperm heads demonstrated equal chromatin replacement during late spermiogenesis. Our results suggest that exf belongs to a unique class of meiotic drive systems in that (1) intranuclear membranous inclusions cause failure of nuclear shaping of Y-bearing spermatids without affecting the histone-protamine transition, and (2) a portion of the aberrant spermatids differentiate into mature sperm; these are transferred to and stored by females.

著者

盛永 俊太郎 栗山 英雄 青木 政春

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.18, no.6, pp.297-304, 1942 (Released:2007-04-04)

参考文献数

1

被引用文献数

1 2

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(1) Some clonal individuals of a haploid plant of Dekiyama produced, in 1933, several diploid tillers which were normal in every respects (1). In the self pollination progenies traced back to those diploid tillers, certain lines in 1936 segregated, besides the normal plants, very small and sterile individuals nearly in a monohybrid recessive ratio (Table 1). A majority of the normal plants also segregated the dwarf type next year in the same ratio.(2) At germination, most of the seeds which develop into the dwarf produce hairs very poorly on the epiblast and coleorhiza (Fig. 3). Though the dwarf is discriminated from the normal even in the first foliage stage, the distinction of the two types becomes very clear with the development of the second leaf on account of its short and narrow sheath and short and curved blade.(3) The upper epidermis of the young dwarf leaf is very characteristic for its far larger number of bulliform cells and the shortness of the ripple wall ones (Figs. 7 and 8).(4) The dwarf grows more slowly in length than the normal, though it tillers more quickly. The dwarf in maturity is smaller than the normal in every respects of the plant, and the height of the plant is only about 1/4 of that of the normal (Table 3). The development of the flower organs is poor, and no seeds are produced.(5) Micro- and megasporogenesis is carried through very regularly in the dwarf, but it can not produce any viable pollen-grains or embryo-sacs. Strange to say, a fairly large percent of ovaries contained two ovules (Fig. 16).(6) We can not tell at present whether this sterile and extremely dwarf mutant is caused by a simple factor mutation or by a loss of a small portion of a chromosome.

著者

神名 勉聰

出版者

日本遺伝学会

雑誌

遺伝学雑誌 (ISSN:0021504X)

巻号頁・発行日

vol.8, no.2-3, pp.165-178, 1933 (Released:2007-11-30)

参考文献数

6

被引用文献数

2 4

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(1) オシロイバナの花色に關與する因子として次のやうなものを檢定した。C, c', c……C は花冠に黄色を表現し、c'は植物體發生の各期を通じて屡ゝCに轉化し、稀にcに轉化する。但しc及びc'は黄色色素の生成能力を缺く。C, c', c を multiple allelomorphs を構成する。R, r',r……R は單獨では cotyledon の裏面を淡赤色に染めるのみで、花色には何等の色をも表現しないが、C と anthocyan 生成に關し補足的關係を結び、花色を赤色ならしめる。r'は植物體發生の各期を通じ常習的にRに轉化し、又稀にrに轉化する。恐らく R, r', r は multiple allelomorphs をなすものであらう。(2) 之等の因子の結合による花の色調は次の通りである。c'c'RR……白色地に赤色條斑CCr'r'……黄色地に赤色條斑Cc'Rr'……淡紅色CCRR……紅色CCRr'……黄紅色地に赤色條斑Cc'RR……淡黄紅色地に赤色條斑Cc'r'r'……淡黄色地に赤色條斑c'c'Rr'……白色地に赤色條斑c'c'r'r'……白色地に赤色•黄色の條斑 (三色條斑型)CCrr……黄色Ccrr……淡黄色ccRR, ccRr, ccrr…白色(3) 雜婚の兩親に使用した白色條斑種 (c'c'RR) と黄色條斑種 (CCr'r') とでは、因子の轉化率の上に大分相違があり、前者では35.04%,後者では4.40%の赤色個體を混生した。この開きはc'及びr'の特性に歸すべきではなく、他の形容因子の働によるものである。(4) c'はCに屡ゝ轉化すると共に、時折cにも轉化する。斯く發現したcは更にC又はc'に轉化することがある。r'も亦R及びrに轉化する特性を有する。(5) 營養體上に起る因子轉化は、所謂第一層にのみ惹起されることが多く、第二層に起ることは比較的稀である。枝變りは、前者の場合では非遺傳性紅色となり、後者の場合には花冠の内方のみ淡紅色となり、次世代に因子の轉化に基く分離が起る。

著者

Sachiko Tomioka Toshiro Aigaki Takashi Matsuo

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.87, no.5, pp.323-329, 2012 (Released:2013-02-13)

参考文献数

13

被引用文献数

2 7

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Insect odorant-binding proteins function in the sensing of odors, tastes, and pheromones. Genes encoding two odorant-binding proteins, Obp57d and Obp57e, were identified to be involved in the behavioral adaptation of Drosophila sechellia to its host plant. The two genes are expressed in cells associated with taste sensilla on the legs, and the expression pattern in the legs is conserved among closely related species. To identify the cis-regulatory elements necessary for the expression in the leg sensilla, the promoter sequences of Obp57d and Obp57e were compared among species. Two types of conserved sequence-motifs were found as candidate cis-regulatory elements. Functions of these conserved elements in the promoters of D. melanogaster Obp57d and Obp57e were examined by using a newly constructed vector that combines the advantages of φC31 integrase-based transformation and gypsy transposable-element-derived insulators. By GFP-reporter assay using the new vector, it was confirmed that these conserved elements are necessary for the expression in the legs, working synergistically with each other to affect the expression level. Single-nucleotide substitutions in these elements dramatically changed the promoter activity. These results provide insight into the molecular mechanism for evolution of adaptive behavior via modulation of OBP expression levels.

著者

Kanako Kawaura Asuka Saeki Takehiro Masumura Shigeto Morita Yasunari Ogihara

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.86, no.4, pp.249-255, 2011 (Released:2011-12-29)

参考文献数

23

被引用文献数

3 8 2

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The plant chondriome confers a complex nature. The atp4 gene (formerly called orf25) of Aegilops crassa (CR) harbors the promoter sequence of the rps7 gene from common wheat (Triticum aestivum cv. Chinese Spring, CS). The rps7 gene of CR has the promoter sequence of CS atp6. The atp6 gene of CR contains an unknown sequence inside of its coding region. Since repeat sequences have been found around the breaking points, these structural alterations are most likely generated through homologous recombination. In this study, PCR analysis was performed to detect structural alterations in each of three lines: euplasmic lines of Ae. crassa, Chinese Spring, and alloplasmic Chinese Spring wheat with the cytoplasm of Ae. crassa ((cr)-CS). We found that each of these lines contained both genotypes, although mitochondrial genotypes of CR in Chinese Spring wheat and CS genotypes in Ae. crassa were still retained as minor fractions (less than 10%). On the other hand, CS mitochondrial gene frequencies in ((cr)-CS) were shown to be ca. 30%. SNP analysis after DNA sequencing of these genes indicated that minor types of all three mitochondrial genes in alloplasmic wheat contained the mitochondrial gene types from pollens. Since the frequencies of paternal mitochondrial gene types in F1 were about 20%, successive backcrossing increased the frequencies of paternal mitochondrial gene types to around 30% in alloplasmic wheat. Expression profiles of these mitochondrial genes were quantitatively analyzed by RT-PCR. Transcripts of paternal mitochondrial gene types were scarcely found. This suggests that minor fractions including paternal mitochondrial gene types are maintained and silenced in the descendants.