Activation of a cryptic splice site in the tax gene of HTLV-I by a single nucleotide change.
We identified a T-to-C mutation 2 nucleotides (nt) upstream from the AG in a GT-AG intron between exons 2 and 3 in the human T-cell leukemia virus type I (HTLV-I) tax mRNA. This mutation resulted in the preferential usage of an alternative splice site, causing a 75-nt elongation of tax mRNA and reduced production of viral antigens. When the clone containing this T-to-C mutation was reverted to the wild-type (T) DNA sequence, normal splicing of tax mRNA ensued and viral production was restored. These results suggest that the nucleotide at the position 2nt upstream from the AG in a GT-AG intron is important for the proper splicing of the HTLV-I tax gene, although it is not considered important for splicing in eukaryotes.
Ohsugi
Takeo
T
Division of Microbiology and Genetics, Center for Animal Resources and Development, Institute of Resource Development and Analysis, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan. ohsugi@gpo.kumamoto-u.ac.jp
D017398:Alternative Splicing; D001483:Base Sequence; D016355:Genes, pX; D006801:Humans; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D012333:RNA, Messenger / Q000378:metabolism
D012333:RNA, Messenger