脊尾白虾血细胞全长cDNA文库的构建及EST序列分析

Construction of a cDNA library from the haemocytes of Exopalaemon carinicauda and analysis of partial expressed sequence tags

A haemocyte cDNA library of Exopalaemon carinicauda was constructed by SMART^TM technology. We determined that the titer of the primary cDNA library was 2.8 × 10⁶ pfu/mL, the recombinant efficiencies were over 99%, the insert size of the library was between 400 bp and 2 000 bp, and the titer of the amplified cDNA library was 4.3 × 10⁹ pfu/mL. One hundred single clones were selected randomly to screen for primary detection and a total of 95 high quality ESTs, averaging 493 bp, were obtained. The ESTs were assembled into 70 unigenes, comprising 11 contigs and 59 singlets. When compared with the public database by Blast, 20 unigenes were highly homologous (E-value < 1e-5) to known genes, two unigenes were unknown genes (hypothetical protein), and 48 unigenes had no significant homology to any sequence. Several functional genes of E. carinicauda, including Troponin I, Enolase, Anti-lipopolysaccharide factor and Lysozyme, were identified by homology comparison. The quality of this haemocyte cDNA library is of a high enough standard to obtain haemocyte-specific expression gene information. These results provide important information on functional genes and lay the groundwork for screening of molecular markers in E. carinicauda.