Se Won Kang

Molecular cloning and expression pattern of 14-3-3ζ from the malaria vector, Anopheles sinensis

14‐3‐3 proteins are known to play a pivotal role in cell survival, apoptosis and signal transduction. The 14‐3‐3ζ isoform has been cloned and characterized from many eukaryotic organisms, including the fruit fly and silkworm. However, no study on mosquito 14‐3‐3 has been reported to date. In an attempt to investigate the function of 14‐3‐3 in midgut epithelial cells undergoing apoptosis, a cDNA library was generated from the malaria vector, Anopheles sinensis, which was treated with apoptosis‐inducing Actinomycin‐D. We were able to identify and obtain A. sinensis 14‐3‐3ζ cDNA (Ansi14‐3‐3ζ) from expressed sequence tags (EST) analysis after conducting massive sequencing of the A. sinensis cDNA library. Ansi14‐3‐3ζ has very high homology to 14‐3‐3 homologs of various insects, such as Anopheles gambiae (100%), Aedes aegypti (100%), Drosophila melanogaster (96%), Bombyx mori (93%), Apis mellifera (93%) and Mus musculus (81%), indicating that mosquito 14‐3‐3ζ is a highly conserved gene in diverse organisms. Analysis of temporal expression patterns showed that Ansi14‐3‐3ζ mRNA is highly expressed in egg, early pupae and adult stages and is also expressed, although at low levels, in fourth instar larvae and late pupae. In response to two immune elicitors (lipopolysaccharide and laminarin), no striking induction of 14‐3‐3ζ mRNA was observed in A. sinensis. Further studies of the precise biological function, inducibility and subcellular distribution of 14‐3‐3ζ are required in Plasmodium invasion‐induced apoptotic midgut cells in A. sinensis in the context of the Time Bomb model.

Molecular phylogenetic study of the endangered land snail Satsuma myomphala based on metallothionein gene

Metallothionein (MT) family of metal-binding proteins are involved in maintaining homeostasis and heavy metal poisoning. Recently, MT has been considered as a biomarker that can identify a particular species, very similar to the use of cytochrome oxidase I (COI) gene. Satsuma myomphala species of land snails have been reported from North-East Asia, including South Korea and Japan. In particular, the land snail species have been known from only a limited area of Geoje Island, Gyeongsangnam-do province of South Korea. Genetic studies of S. myomphala has been limited with only 6 nucleotide, 2 protein registered on the NCBI server. For elucidating the genetic information of S. myomphala, we conducted RNA sequencing analysis using Illumina HiSeq 2500 next-generation platform. We screened the MT gene from the RNA-Seq database to confirm the molecular phylogenetic relationship. After sequencing, the de novo analysis and clustering generated 103,774 unigenes. After annotation against PANM database using BLAST program, we obtained MT sequence of 74 amino acid residues containing the coding region of 222 bp. Based on this sequence, we found about 53 sequences using the BLAST program in NCBI nr database. Using ClustalX alignment, Maximum-Likehood Tree of MEGA program, we confirmed the molecular phylogenetic relationships that showed similarity with mollusks such as Helix pomatia and H. aspersa, Megathura crenulata.