Linkage mapping of developmentally expressed cDNAs containing AT-rich elements in shrimp (Litopenaeus vannamei) - Differential expression after challenge with Taura Syndrome Virus (TSV)
Coastal Sciences, Gulf Coast Research Laboratory
To explore the possibility of finding interleukin-like gene(s) in Litopenaeus vannamei shrimp, we sought evidence for the presence of interleukin 1 (IL-1)-like genes, because the proteins encoded by these genes are evolutionarily conserved. RTPCR performed with primers from conserved regions of vertebrate IL-1 alpha genes amplified three bands of 954 by (ShIL1-21; accession # U94689), 864 by (ShIL1-28; U94690), and 182 by (ShIL1-J17; U94691) from various tissues. The cDNA sequences were AT-rich (similar to 65%) and contained 1-5 copies of the "ATTTA" motif, a possible indicator of mRNA degradation. GenBank search indicated that similar AT-rich elements are present in the 3'-untranslated regions (UTR) of vertebrate cytokines, growth factors and other tissue-specific and developmentally expressed genes. Northern blot hybridization analysis using ShIL1-21 as probe detected mRNA transcripts of similar to 1.8 kb and similar to 2.9 whereas ShIL1-28 detected a similar to 7.5 kb transcript. All transcripts showed tissue and developmental variations in their mRNA expression. The 1.8 kb transcript of ShIL 1-21 was expressed at high levels in postlarvae stage 8 (PL8) but not in Zoea stage 2/3 or tail muscle of juvenile and adult shrimp. The 7.5 kb mRNA of SHIL 1-28 was present in tail muscle of adult female shrimp but not in male tail muscle. In addition, all transcripts levels increased in juveniles at 24 h and 36 h after TSV challenge indicating that the expression of these genes is modulated during TSV infection. Primer sets flanking simple sequence repeats in ShIL1-21 and ShIL1-28 amplified polymorphic alleles in L. vannamei from various geographic regions, suggesting that these markers will be useful for genetic diversity analyses. ShIL1-21 and ShIL1-28 primers were used for genotyping with the entire international reference mapping family (IRM F) panel developed for construction of a linkage map for shrimp (ShrimpMap). CRIMAP analysis using a limits-of-detection (LOD) score of 5.0 placed ShIL1-21 in linkage group 14 of ShrimpMap whereas ShIL1-28 remained unlinked. The parental alleles segregated in a Mendelian fashion indicating that these genes are useful for pedigree tracing and population analysis.
Journal of Shellfish Research
Dhar, A. K.,
Carr, W. H.,
Lotz, J. M.,
(2007). Linkage mapping of developmentally expressed cDNAs containing AT-rich elements in shrimp (Litopenaeus vannamei) - Differential expression after challenge with Taura Syndrome Virus (TSV). Journal of Shellfish Research, 26(4), 1217-1224.
Available at: http://aquila.usm.edu/fac_pubs/1801