Genes & Genetic Systems
Online ISSN : 1880-5779
Print ISSN : 1341-7568
ISSN-L : 1341-7568
79 巻 , 2 号
選択された号の論文の7件中1~7を表示しています
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  • Yasushi Saeki, Erika Isono, Tomoko Oguchi, Masumi Shimada, Takayuki So ...
    2004 年 79 巻 2 号 p. 77-86
    発行日: 2004年
    公開日: 2004/06/17
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    We constructed polyubiquitin derivatives that contain a tandem repeat of ubiquitins and were insensitive to ubiquitin hydrolases. They were designated tandem ubiquitin (tUb) with the number of repeats, such as tUb2. When tUbs were expressed under the control of the GAL1 promoter in the wild-type yeast strain, growth was strongly inhibited. Under these conditions, the degradation of N-end rule substrates, a UFD substrate and Gcn4 was inhibited, indicating that the tUb inhibits 26S proteasome activity. Consistent with this, tUb binds to the 26S proteasome. We showed that tUb inhibited the in vitro degradation of polyubiquitinylated Sic1 by the 26S proteasome. When tUB6 messenger RNA was injected into Xenopus embryos, cell division was inhibited, suggesting that tUb can be used as a versatile inhibitor of the 26S proteasome.
  • Hiroshi Shiba, Jong-In Park, Go Suzuki, Masanori Matsushita, Ill-Sup N ...
    2004 年 79 巻 2 号 p. 87-93
    発行日: 2004年
    公開日: 2004/06/17
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    Self-incompatibility (SI) discriminating self and non-self pollen is regulated by S-locus genes in Brassica. In most S haplotypes, a set of three highly polymorphic genes, SLG, SRK, and SP11, is located at the S-locus region. In the present study, we found duplicated SP11 genes, S15-SP11a, S15-SP11b, and S15-SP11b’, in the self-incompatible S15 haplotype of B. oleracea. RNA gel blot and reverse transcription polymerase chain reaction (RT-PCR) analyses showed that two different sizes of SP11 transcripts were specifically detected in anther tissues: a 0.65-kb transcript corresponded to S15-SP11a (an exon-1 region of S15-SP11b was also co-transcribed in some cases), and a 1.4-kb transcript contained the duplicated three genes, S15-SP11a, S15-SP11b, and an exon-1 region of S15-SP11b’, all three of which were connected to intergenic spacer regions.
  • Koichiro Tsunewaki
    2004 年 79 巻 2 号 p. 95-104
    発行日: 2004年
    公開日: 2004/06/17
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    Of the various chlorophyll abnormalities that occur in polyploid wheats, genetic bases of only two types, chlorina and virescence, are known. Here, for the first time, the chromosomal bases of three other chlorophyll abnormalities, striato-virescence, delayed virescence, and albino, which occur in Emmer wheat (2n = 4x = 28, genome constitution AABB) are reported. A set of disomic substitution lines of Langdon durum was used for chromosome identification. All three abnormalities are controlled by two duplicated recessive genes (carrier chromosome in parentheses); striato-virescence by sv1 (3A) and sv2 (2A), delayed virescence by dv1 (2B) and dv2 (supposedly 2A), and albino by abn1 (2A) and abn2 (2B). Genes on the same chromosome are located in different loci and are recombined with each other. The Chinese Spring cultivar of common wheat (2n = 6x = 42, genome constitution AABBDD) carries wild-type homoeoalleles for these abnormalities; Sv3 (2D), Dv3 (2D), and Abn3 (2D).
  • Masayuki Sumida, Yoji Kato, Atsushi Kurabayashi
    2004 年 79 巻 2 号 p. 105-118
    発行日: 2004年
    公開日: 2004/06/17
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    The rDNA of eukaryotic organisms is transcribed as the 40S-45S rRNA precursor, and this precursor contains the following segments: 5' – ETS – 18S rRNA – ITS 1 – 5.8S rRNA – ITS 2 – 28S rRNA – 3'. In amphibians, the nucleotide sequences of the rRNA precursor have been completely determined in only two species of Xenopus. In the other amphibian species investigated so far, only the short nucleotide sequences of some rDNA fragments have been reported. We obtained a genomic clone containing the rDNA precursor from the Japanese pond frog Rana nigromaculata and analyzed its nucleotide sequence. The cloned genomic fragment was 4,806 bp long and included the 3'-terminus of 18S rRNA, ITS 1, 5.8S rRNA, ITS 2, and a long portion of 28S rRNA. A comparison of nucleotide sequences among Rana, the two species of Xenopus, and human revealed the following: (1) The 3'-terminus of 18S rRNA and the complete 5.8S rRNA were highly conserved among these four taxa. (2) The regions corresponding to the stem and loop of the secondary structure in 28S rRNA were conserved between Xenopus and Rana, but the rate of substitutions in the loop was higher than that in the stem. Many of the human loop regions had large insertions not seen in amphibians. (3) Two ITS regions had highly diverged sequences that made it difficult to compare the sequences not only between human and frogs, but also between Xenopus and Rana. (4) The short tracts in the ITS regions were strictly conserved between the two Xenopus species, and there was a corresponding sequence for Rana. Our data on the nucleotide sequence of the rRNA precursor from the Japanese pond frog Rana nigromaculata were used to examine the potential usefulness of the rRNA genes and ITS regions for evolutionary studies on frogs, because the rRNA precursor contains both highly conserved regions and rapidly evolving regions.
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