Yasuhiko Mukai

Onion, Allium cepa, is a model plant for experimental observation of mitotic cell division in practice of fundamental biology, because its chromosome is big and easy to observe. In order to develop new academic tools for visualization of plant cytokinesis, molecular cloning of onion mitotic genes, which are related to cell division, cell cycle, and chromosome segregation, is indispensable. Here we isolated CDC48 cDNA (AcCDC48) from onion seedlings, which encodes an AAA-ATPase chaperone and is known to play a role in cell division in broad species of organism. To characterize AcCDC48, we performed phylogenetic and DNA gel blot analyses, and discussed about the possible application of mammalian antibodies to detect it. The full-length onion CDC48 sequence provides useful information for future development of molecular markers to visualize cell division by using antibodies or GFP-fusion proteins.

Onion, Allium cepa, is a model plant for experimental observation of mitotic cell division in practice of fundamental biology, because its chromosome is big and easy to observe. In order to develop new academic tools for visualization of plant cytokinesis, molecular cloning of onion mitotic genes, which are related to cell division, cell cycle, and chromosome segregation, is indispensable. Here we isolated CDC48 cDNA (AcCDC48) from onion seedlings, which encodes an AAA-ATPase chaperone and is known to play a role in cell division in broad species of organism. To characterize AcCDC48, we performed phylogenetic and DNA gel blot analyses, and discussed about the possible application of mammalian antibodies to detect it. The full-length onion CDC48 sequence provides useful information for future development of molecular markers to visualize cell division by using antibodies or GFP-fusion proteins.

Four spontaneous chromosomal translocations were previously detected in tetraploid (Triticum turgidum L., 2n=4x=28) wheat landraces from Ethiopia. We identified here the chromosomes involved in the translocations through the application of meiotic analysis using the double-ditelosomic series of the durum wheat variety LD222. The landrace wheat lines, K-1-1, B-3-11 and CD-7 carried 2A/2B, 7A/7B and 4A/4B (?) translocations, respectively. The landrace variety DZ-04-118 carried a cyclic translocation involving three chromosomes, 2A/2B/4B. Translocation 2A/2B in K-1-1 and in DZ-04-118 has the same origin. The chromosomal breakpoints of the homoeologous translocations 2A/2B and 7A/7B were successfully localized using the genomic in situ hybridization (GISH) technique. The breakpoints for translocation 2A/2B were at or close to the centromere region while those of 7A/7B were noncentromeric types. This is the first application of GISH to locating translocation breakpoints between homoeologous chromosomes. Probable mechanisms of origin for homoeologous translocations are discussed.

Four spontaneous chromosomal translocations were previously detected in tetraploid (Triticum turgidum L., 2n=4x=28) wheat landraces from Ethiopia. We identified here the chromosomes involved in the translocations through the application of meiotic analysis using the double-ditelosomic series of the durum wheat variety LD222. The landrace wheat lines, K-1-1, B-3-11 and CD-7 carried 2A/2B, 7A/7B and 4A/4B (?) translocations, respectively. The landrace variety DZ-04-118 carried a cyclic translocation involving three chromosomes, 2A/2B/4B. Translocation 2A/2B in K-1-1 and in DZ-04-118 has the same origin. The chromosomal breakpoints of the homoeologous translocations 2A/2B and 7A/7B were successfully localized using the genomic in situ hybridization (GISH) technique. The breakpoints for translocation 2A/2B were at or close to the centromere region while those of 7A/7B were noncentromeric types. This is the first application of GISH to locating translocation breakpoints between homoeologous chromosomes. Probable mechanisms of origin for homoeologous translocations are discussed.