TY - JOUR
T1 - DNA sequence analysis of a chromosomal aberration in irradiation induced burnt (Bu) mutant of Bombyx mori
AU - Fujii, Tsuguru
AU - Kubo, Maki
AU - Kuwazaki, Seigou
AU - Yamamoto, Kimiko
AU - Ohnuma, Akio
AU - Banno, Yutaka
AU - Shimada, Toru
N1 - Funding Information:
We used three B. mori strains (n70, p50, and F11) that are stored at Kyushu University, with partial support from the National BioResource Project. The n70 strain harbors the burnt (Bu) mutation, creates irregularly shaped fifth to eighth larval segments. p50 is the standard B. mori strain that was used to produce a high-quality genome assembly (Kawamoto et al., 2019). The F11 strain harbors the knob (K) mutation, which creates knobs in the larval integument (Edayoshi et al., 2015). Another strain harboring the non-preference A4 (Np-A4) mutation was provided by the Institute of Sericulture, The Dainippon Silk Foundation. To select larvae carrying the Np-A4 mutation, feeding tests were conducted. Larvae were separated from mulberry leaves at the fourth molting stage. The fifth instar larvae were starved for about 1 day and then placed in a plastic dish with a piece of Brassica campestris var. peru-viridis leaf for 1 hour, to observe whether the larva would feed on the leaf. After the K mutation was introduced into the Np-A4 bearing chromosome 11 by meiotic recombination in males, the resultant chromosome marked by K and Np-A4 was maintained maternally by repeated crossings of K Np-A4 females to p50 males. This procedure was used because there is no recombination in female meiosis (Tanaka, 1916). In this report, the K Np-A4 strain was designated as F08.
Funding Information:
The three B. mori strains (p50, n70, and F11) were pro-vided by the National BioResource Project, Japan. We thank K. Nishikawa, K. Tamura, K. Yamamoto (Laborato-ry of Silkworm Genetic Resources, Institute of Genetic Resources, Graduate School of Bioresources and Bioenvi-ronmental Science, Kyushu University) for rearing silk-worms.
Publisher Copyright:
© 2022, Japanese Society of Sericultural Sciences. All rights reserved.
PY - 2022
Y1 - 2022
N2 - The radiation-induced mutations burnt (Bu) and non-preference A4 (Np-A4) map to chromosome 11 in Bom-byx mori. Bu causes irregularly shaped fifth to eighth larval segments, whereas Np-A4 causes one of the po-lyphagous phenotypes, i.e., feeding on non-mulberry leaves. Homozygotes and trans heterozygotes of these mutations die during embryogenesis, suggesting that the lethality associated with Bu and Np-A4 is allelic. Genetic studies of the Bu and Np-A4 mutation would provide a better understanding of the embryogenesis, mor-phogenesis, and feeding behavior of B. mori. Here we conducted a molecular analysis of the Bu locus. In our crossing experiments, larvae carrying both the Bu and Np-A4 mutations appeared, although they were hypoth-esized to die during embryogenesis. A detailed analysis of the survivors resulted in the identification of a breakage event on chromosome 11. Moreover, it was revealed that the survivors exhibited partial trisomy. Using DNA sequence analysis, the breakpoint in chromosome 11 was narrowed to an intron of Bmzfh3. Embryonic lethality associated with the breakage of the chromosome 11 is discussed.
AB - The radiation-induced mutations burnt (Bu) and non-preference A4 (Np-A4) map to chromosome 11 in Bom-byx mori. Bu causes irregularly shaped fifth to eighth larval segments, whereas Np-A4 causes one of the po-lyphagous phenotypes, i.e., feeding on non-mulberry leaves. Homozygotes and trans heterozygotes of these mutations die during embryogenesis, suggesting that the lethality associated with Bu and Np-A4 is allelic. Genetic studies of the Bu and Np-A4 mutation would provide a better understanding of the embryogenesis, mor-phogenesis, and feeding behavior of B. mori. Here we conducted a molecular analysis of the Bu locus. In our crossing experiments, larvae carrying both the Bu and Np-A4 mutations appeared, although they were hypoth-esized to die during embryogenesis. A detailed analysis of the survivors resulted in the identification of a breakage event on chromosome 11. Moreover, it was revealed that the survivors exhibited partial trisomy. Using DNA sequence analysis, the breakpoint in chromosome 11 was narrowed to an intron of Bmzfh3. Embryonic lethality associated with the breakage of the chromosome 11 is discussed.
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U2 - 10.11416/jibs.91.3_041
DO - 10.11416/jibs.91.3_041
M3 - Article
AN - SCOPUS:85144301857
SN - 1346-8073
VL - 91
SP - 41
EP - 50
JO - Journal of Insect Biotechnology and Sericology
JF - Journal of Insect Biotechnology and Sericology
IS - 3
ER -