Gene expression profiles in acholeplasma-treated fat body cells of Tenebrio moliter

Tenebrio moliter, a colepoteran insect, has been used as a model insect to study innate immune responses against Gram +/‐ bacteria containing peptidoglycan. However, little is known about the gene expression profiles of fat body cells in response to Aholeplasma which does not have peptidoglycan. In the present study, we analyzed the transcriptome changes of Tenebrio fat body cells in response to Acholeplasma. To conduct comparative transcriptome analysis between Acholeplasma‐untreated control fat cells (C) and Acholeplasma‐treated fat cells (T), two independent normalized cDNA libraries were constructed. Analysis of the 4,032 (C, 2,016; T, 2,016) expression sequence tags (ESTs) generated from these libraries identified 495 contigs (C, 256; T, 239) and 2,690 singletons (C, 1340; T, 1350) with average lengths of 745 bp (C) and 683 bp (T), respectively. In silico analysis indicates that the expression of genes encoding cytochrome c oxidase subunit I, desiccation stress protein, 13 kDa hemolymph protein, galactose‐binding lectin, beta‐glucosidase, t1/t2 receptor binding protein and various hypothetical proteins increased by 5‐fold. In contrast, the expression of genes encoding early‐staged encapsulation‐inducing protein, hexamerin 2 precursor, melanin‐inhibiting protein, myospheroid and tetraspanin D107 decreased by at least 4‐fold (up to 21‐fold). Yet, it remains to further clarify the expression level of the up‐/down‐regulated genes in response to Acholeplasma using PCR, and elucidate the biological significance of these genes using RNAi and biochemical analyses.