CHARACTERIZATION OF A RAINBOW-TROUT MX-GENE

A full-length cDNA clone of a rainbow trout (Oncorhynchus mykiss) Mr g ene was obtained using RACE (rapid amplification of cDNA ends) polymer ase chain reaction (PCR) amplification of RNA extracted from poly (I) (C)-induced rainbow trout gonad cells (RTG-2). Mx was previously ident ified in rainbow trout by Staeheli et al.((1)) by hybridization with a partial perch genomic Mr probe to induced rainbow trout mRNA, The 2.5 kb rainbow trout cDNA clone contains an open reading frame of 1863 nt (nucleotides) encoding a 621 amino acid protein, The deduced rainbow trout Mr protein is 70.6 kD and contains the characteristic tripartite GTP binding motif common to all Mr proteins, Southern blot analysis w ith the rainbow trout Mr probe demonstrated the presence of Mr homolog ous genes in four other salmonid fish species, including chinook, coho , and kokanee salmon and brook trout, Poly (I) (C) treatment of both R TG-2 and chinook salmon cells (CHSE-214) induced two transcripts whose appearance was observed first at 24 h and as long as 72 h after treat ment, Infection of rainbow trout with the salmonid rhabdovirus, IHNV ( infectious hematopoietic necrosis virus), also induced the synthesis o f Mr mRNA, A comparison of the rainbow trout Mr protein with other rep orted Mr proteins indicates that the piscine Mr is highly homologous t o the mammalian Mr proteins,