Searching for immunomodulatory sequences in sea bass (Dicentrarchus labrax L.): Transcripts analysis from thymus

Abstract

The thymus is a key organ of the immune system in most vertebrates and, for this reason, it has been used in this paper for the generation of a normalized cDNA library from sea bass (Dicentrarchus labrax), one of the most extensively cultured species in South Mediterranean aquaculture. A total of 1632 ESTs from this library were initially analysed for sequence quality and vector sequences and, after this control, 1264 (77% of total clones sequenced) high-quality ESTs were further processed. The total collection of D. labrax thymus ESTs has been deposited in the EBI-GenBank-DBJ database (GenBank accession numbers from FN565576 to FN566839). The functional classification of ESTs was performed by Gene Ontology and KEGG annotation and, successively, the sequences were analysed using the ImmunomeBase software to identify potentially immuno-related genes. Using this approach, we found about 100 putative genes involved in immune system responses, most new in sea bass, that were analysed more in detail. Some of the potentially interesting genes identified by these in silico analyses were studied by real-time PCR to verify their expression both at basal level and after in vitro stimulation of sea bass head kidney leukocytes. The used strategy has been confirmed as a good approach to discover new immuno-related genes and to improve the knowledge of specific markers that could help the discrimination of T-cell subpopulations in sea bass and, in general, in Teleosts.

A formalin-inactivated immunogen against viral encephalopathy and retinopathy (VER) disease in European sea bass (Dicentrarchus labrax): immunological and protection effects

“…Two different Mx genes had been identified in European sea bass, proving that the isoform MxA is particularly modulated in nodavirus-infected sea bass [20, 46]. As previously shown [47], the ISG12 gene can also be employed in sea bass as a marker of antiviral activities, since this ISG isoform is well expressed in gills [22], and significant ISG12 gene modulation can be induced in sea bass after in vitro stimulation with virus-mimicking substance poly I:C [47]. …”

Revisiting the Teleost Thymus: Current Knowledge and Future Perspectives

“…As mentioned above, in mammals, DN cells undergo V(D)J rearrangement to express TCR α and β-chains. Several studies reported the expression of Rag-1 and Rag-2 located in the thymus of zebrafish, rainbow trout, red-spotted grouper (Epinephelus akaara), medaka, goldfish (Carassius auratus), fugu, carp, Atlantic salmon and Atlantic halibut [74][75][76][77][78][79][80][81][82][83]. The rag gene expression suggested a conserved mechanism for TCRβchain rearrangement which is a crucial step for pre-TCR expression.…”

A CD83-like molecule in sea bass (Dicentrarchus labrax): Molecular characterization and modulation by viral and bacterial infection

“…CD83 sequence was identified after Expressed Sequence Tag (EST) sequencing of a sea bass thymus cDNA library as described previously [17]. The library was normalized to facilitate the identification and analysis of rare transcripts.…”