AUTHOR=Yin Bin , Wang Haiyang , Zhu Peng , Weng Shaoping , He Jianguo , Li Chaozheng 

TITLE=A Polymorphic (CT)n-SSR Influences the Activity of the Litopenaeus vannamei IRF Gene Implicated in Viral Resistance

JOURNAL=Frontiers in Genetics

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2019.01257

DOI=10.3389/fgene.2019.01257

ISSN=1664-8021

ABSTRACT=<p>Simple sequence repeats (SSRs) of short nucleotide motifs occur very frequently in the 5′ untranslated coding region (5′-UTR) of genes and have been implicated in the regulation of gene expression. In this study, we identified an SSR with a variable number of CT repeats in the 5′-UTR of the <italic>Litopenaeus vannamei IRF</italic> (<italic>LvIRF</italic>) gene that has been shown to mediate antiviral responses by inducing the expression of Vago, a functional homolog of mammalian IFN. We then explored the effects of varying the number of (CT)<italic>n</italic> repeats on the expression of <italic>LvIRF</italic> using both dual-luciferase reporter assays and Western blots. Our results demonstrate that the length of the (CT)<italic>n</italic>-SSR in this gene can influence the expressional level of <italic>LvIRF</italic>, in that a shorter (CT)<italic>n</italic> repeat had a stronger ability to induce the expression of <italic>LvIRF</italic>. Moreover, we found that the (CT)<italic>n</italic> repeat in <italic>LvIRF</italic> was associated with viral resistance in shrimp. Individual shrimps with shorter (CT)<italic>n</italic> repeats in the 5′-UTR of <italic>LvIRF</italic> exhibited high tolerance to white spot syndrome virus (WSSV), and this trait was inherited in offspring. Taken together, these results indicated that this (CT)<italic>n</italic>-SSR could be used as a molecular marker for shrimp breeding for WSSV resistance.</p>