Expression Analysis of jam-as in GCRV-infected Grass Carp (Ctenopharyngodon idellus) PSF Cells and During the Embryo and Juvenile Stages

Abstract:

Grass carps are seriously threatened by GCRV (grass carp reovirus) that can cause high mortality to fingerling and yearling grass carps. Grass carp snout fibroblast cells (PSF) are highly sensitive to GCRV. Junctional adhesion molecule A (JAM-A), an immunoglobulin superfamily member, acts as a viral cell receptor. In our previous study, the cDNA sequences of grass carp jam-a1, jam-a2, and jam-a3 (named gcjam-a1, gcjam-a2, and gcjam-a3) were cloned. Based on this, qRT-PCR was used to analyze the expression pattern of gcjam-as at different embryonic and juvenile development stages and in GCRV-GD108-infected PSF cells. The results showed that the expression pattern of gcjam-a1, 2, and 3 differed during the embryonic development stages. mRNA expression of gcjam-a1 could be detected in unfertilized eggs and at a lower level from the fertilized egg stage to 1 dph (day post hatch). However, the mRNA was highly expressed at 1~3 dph and high levels were maintained from 3 dph to the end of the experiment (15 dph). The expression of gcjam-a2 and gcjam-a3 was very low at different embryonic development stages compared to that of gcjam-a1. gcjam-as were only slightly expressed in non-infected PSF cells. After GCRV-GD108 infection, the expression of S7 in PSF cells increased significantly, and the expression of gcjam-as in PSF cells also increased to different levels after GCRV-GD108 infection. Upregulation of the gcjam-as was in the order: gcjam-a1> gcjam-a2>gcjam-a3. The results showed that the expression of jam-as was related to GCRV infection in PSF cells and that the expression of jam-a1 was most influenced by GCRV-GD108 infection. It is also expressed in early embryonic development, suggesting that jam-a1 is the most relevant to GCRV infection. This study will lay the foundation for further research on GCRV receptors.