Fujii Takeshi, Yasukochi Yuji, Rong Yu, Matsuo Takashi, Ishikawa Yukio
Laboratory of Applied Entomology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan.
Insect Genome Research Unit, National Institute of Agrobiological Sciences, Tsukuba, Ibaraki 305-8634, Japan.
Insect Biochem Mol Biol. 2015 Jun;61:62-8. doi: 10.1016/j.ibmb.2015.04.007. Epub 2015 May 2.
Regulation of the expression of fatty acyl-CoA desaturases, which introduce a double bond into the fatty acid moiety of the substrate, is crucial for the production of species-specific sex pheromones in moths. In Ostrinia moths, two distinct Δ11-desaturases and a Δ14-desaturase are known to be selectively used in the biosynthesis of sex pheromones. Of the two Δ11-desaturases, one identified from Ostrinia nubilalis and Ostrinia scapulalis, Z/EΔ11, forms the Z and E isomers of a double bond at position 11, whereas the other identified from Ostrinia latipennis, LATPG1(=EΔ11), exclusively forms an E double bond at position 11. Since the retroposon(ezi)-fused, non-functional Δ11-desaturase gene, ezi-Δ11α, in the genomes of O. nubilalis and O. furnacalis was previously suggested to be an orthologue of latpg1, we here explored Z/EΔ11 orthologues in the genome of O. latipennis. We newly identified two Δ11-desaturase genes, latpg2 and latpg3, which were orthologous to ezi-Δ11β and Z/EΔ11, respectively. We found that an ezi-like element was integrated in intron 1 of latpg1, and confirmed that only latpg1 was expressed in the pheromone gland of O. latipennis. Thus, at least three Δ11-desaturase genes are present in the genome of O. latipennis, and latpg1 is selectively transcribed in the pheromone gland of this moth. The non-functionality of ezi-inserted desaturase genes in O. nubilalis and O. furnacalis may not be a direct consequence of the insertion of an ezi- or ezi-like element into the gene.
脂肪酸酰基辅酶A去饱和酶可将双键引入底物的脂肪酸部分，其表达调控对于蛾类物种特异性性信息素的产生至关重要。在玉米螟蛾中，已知两种不同的Δ11-去饱和酶和一种Δ14-去饱和酶被选择性地用于性信息素的生物合成。在这两种Δ11-去饱和酶中，一种从欧洲玉米螟和亚洲玉米螟中鉴定出的Z/EΔ11，在第11位形成双键的Z型和E型异构体，而另一种从宽翅玉米螟中鉴定出的LATPG1（=EΔ11），仅在第11位形成E型双键。由于先前认为欧洲玉米螟和亚洲玉米螟基因组中逆转座子（ezi）融合的无功能Δ11-去饱和酶基因ezi-Δ11α是latpg1的直系同源物，我们在此探索了宽翅玉米螟基因组中的Z/EΔ11直系同源物。我们新鉴定出两个Δ11-去饱和酶基因latpg2和latpg3，它们分别与ezi-Δ11β和Z/EΔ11直系同源。我们发现一个ezi样元件整合在latpg1的内含子1中，并证实只有latpg1在宽翅玉米螟的性信息素腺中表达。因此，宽翅玉米螟基因组中至少存在三个Δ11-去饱和酶基因，且latpg1在该蛾的性信息素腺中被选择性转录。欧洲玉米螟和亚洲玉米螟中ezi插入的去饱和酶基因的无功能可能不是ezi或ezi样元件插入该基因的直接结果。
