Nucleotide sequence of the 3' non-coding region and N gene of the S RNA of a serologically distinct tospovirus

Abstract

A tomato spotted wilt-like virus (TSWV-I) is a distinct member of the Tospovirus genus of the Bunyaviridae and is distinguished from the typical TSWV by having a serologically distinct nucleoprotein (N). A cDNA clone extending from the 3' terminus of the viral RNA through the entire N open reading frame (ORF) was sequenced. The TSWV-I N ORF is capable of encoding a polypeptide of 262 amino acids with a predicted Mr of 28.8K. In vitro transcription and translation of the clone produced a protein which comigrated with TSWV-I N and was immunoprecipitated by TSWV-I antibodies. Hybridization analysis of lithium chloride-precipitated RNA from healthy and TSWV-I-infected tissue detected a virus-specific 1.2 kb subgenomic RNA. The TSWV-I S RNA terminal consensus sequence (8 nucleotides) was identical to that of TSWV; the remaining TSWV-I untranslated region showed only 51% identity with that of TSWV. Comparison of the TSWV-I and TSWV N proteins showed 67% identity at the amino acid level. The degree of similarity in the terminal sequence, untranslated region and N ORF is similar to that expected between distinct serogroups within certain genera of the Bunyaviridae.