First molluscan transcription factor activator protein-1 (Ap-1) member from disk abalone and its expression profiling against immune challenge and tissue injury

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P><P>The regulation of transcriptional activation is an essential and critical point in gene expression. In this study, we describe a novel transcription factor activator protein-1 (Ap-1) gene from disk abalone <I>Haliotis discus discus</I> (AbAp-1) for the first time in mollusk. It was identified by homology screening of an abalone normalized cDNA library. The cloned AbAp-1 consists of a 945 bp coding region that encodes a putative protein containing 315 amino acids. The AbAp-1 gene is composed of a characteristic Jun transcription factor domain and a highly conserved basic leucine zipper (bZIP) signature similar to known Ap-1 genes. The AbAp-1 shares 46, 43 and, 40% amino acid identities with fish (<I>Takifugu rubripes</I>), human and insect (<I>Ixodes scapularis</I>) Ap-1, respectively.</P><P>Quantitative real time RT-PCR analysis confirmed that AbAp-1 gene expression is constitutive in all selected tissues. AbAp-1 was upregulated in gills after bacteria (<I>Vibrio alginolyticus, Vibrio parahemolyticus</I> and <I>Lysteria monocytogenes</I>) challenge; and, upregulated in hemocytes and gills by viral hemorrhagic septicemia virus (VHSV) challenge. Shell damage and tissue injury also increased the transcriptional level of Ap-1 in mantle together with other transcription factors (NF-kB, LITAF) and pro-inflammatory TNF-α. All results considered, identification and gene expression data demonstrate that abalone Ap-1 is an important regulator in innate immune response against bacteria and virus, as well as in the inflammatory response during tissue injury. In addition, stimulation of Ap-1 under different external stimuli could be useful to understand the Ap-1 biology and its downstream target genes, especially in abalone-like mollusks.</P>