Jin-Sung Lee

Cloning of the fibroin gene from the oak silkworm, Antheraea yamamai and its complete sequence

The nucleotide sequences containing an entire genomic region and 5′ upstream region of Antheraea yamamai fibroin gene have been determined. The gene consists of an initial exon encoding 14 amino acids, an intron (150 bp), and a long second exon coding for 2641 amino acids. The fibroin coding sequence shows a specialized organization with a highly repetitive region flanked by non repetitive 5′ and 3′ ends. Northern blot analyses confirmed that fibroin gene is actively expressed in the posterior silk gland of the final instar larvae of Antheraea yamamai.

Gene Expression Profiling in the Silkworm, Bombyx mori, During Early Embryonic Development

Abstract We prepared a cDNA library for a microarray from eggs of the silkworm, Bombyx mori, at the germ-band formation (24 hours after fertilization) stage. Using a microarray constructed with 2,445 ESTs, we screened gene expression profiles during germ-band formation at six specific time points in the early embryonic stages (from the unfertilized egg to the formation of abdominal leg appendages), and determined 241 of these cDNAs to represent genes that were expressed differentially during the germ-band formation stage. These differentially expressed genes grouped into two clusters. In the early and late clusters, 203 and 38 genes were upregulated, respectively. In the upregulated clusters, we isolated several genes that were associated with development and cell communication, including egalitarian, RAD23b, innexin 2, and senescence-associated protein. Northern blot hybridization revealed that the expression patterns of 14 genes had changed in each of the stages. In this study, we assessed changes in the levels of gene expression in relation to the germ-band formation stages in whole Bombyx embryos.

Molecular genetic relationships between Bombycidae and Saturniidae based on the mitochondria DNA encoding of large and small rRNA.

The phylogenetic relationships between Bombycidae (Bombyx mori and Bombyx mandarina) and Saturniidae (Antheraea yamamai and Antheraea pernyi) were investigated based on large and small mitochondiral rRNA genes. About 430 bp of four kinds of PCR-amplified fragments were sequenced and aligned. For the 16S rRNA gene, B. mori shared a 98, 87 and 86% sequence homology with B. mandarina, A. yamamai and A. pernyi, and for the 12S rRNA gene, B. mori shared a 99, 89 and 88% sequence homology with B. mandarina, A. yamamai and A. pernyi, respectively. DNA sequence data were also used for a phylogenetic analysis. All of the trees showed monophyly for both Bombycidae and Saturniidae. The monophyly confidence limits of these trees were estimated using bootstrapping tests and measured more than 99% for all trees for both Bombycidae and Saturniidae.

The Comparative Molecular Study between Bombycidae and Saturniidae Based on mtDNA RFLP and Cytochrome Oxidase I Gene Sequences: Implication for Molecular Evolution

Abstract Bombycidae, Saturniidae, mtDNA RFLP, Cytochrome Oxidase I Gene The phylogenetic relationships between Bombyx mori and Bombyx mandarina species of Bombycidae, and Antheraea yamamai and Antheraea pernyi species of Saturniidae were investigated based on mtDNA RFLP and cytochrome oxidase I gene. The sizes of the mtDNA of all the species were estimated at approximately 16 kbp ± 500 bp by total length of all the restricted fragments and no variation in size was recognized. Of the fourteen different restriction endonucleases used, BamHl, Hindlll, Pstl, EcoRl and Xbal showed RFLP. Among these, only Hindlll showed RFLP between B. mori and B. mandarina. A comparative analysis of sequences was also conducted with the mitochondrial cytochrome oxidase I genes of each species. The results indicated that B. mori shared a 97% , 85% and 87% sequence identity with B. mandarina, A. yamamai and A. pernyi, respectively. B. mandarina shared a 87% and 88% sequence identity with A. yamamai and A. penyi, respectively. A. yamamai shared 92% sequence identity with A. pernyi. The results of the phylogenetic analysis exhibited monophyly and confidence limits of more than 99% in all trees for both Bombycidae and Saturniidae.

Isolation of Genes Specifically Expressed in Different Developmental Stages of Pleurotus ostreatus Using Macroarray Analysis

Abstract The oyster mushroom (Pleurotus ostreatus) is one of the most important edible mushrooms worldwide. The mechanism of P. ostreatus fruiting body development has been of interest both for the basic understanding of the phenotypic change of the mycelium-fruiting body and to improve breeding of the mushrooms. Based on our previous publication of P. ostreatus expressed sequence tag database, 1,528 unigene clones were used in macroarray analysis of mycelium, fruiting body and basidiospore developmental stages of P. ostreatus. Gene expression profile databases generated by evaluating expression levels showed that 33, 10, and 94 genes were abundantly expressed in mycelium, fruiting body and basidiospore developmental stages, respectively. Among them, the genes specifically expressed in the fruiting body stage were further analyzed by reverse transcription-polymerase chain reaction and Northern blot to investigate temporal and spatial expression patterns. These results provide useful information for future studies of edible mushroom development.