A yeast sigma composite element, TY3, has properties of a retrotransposon.

摘要: Sigma is a 340- or 341-base pair repetitive element which located almost exclusively within 19 base pairs of the 5' ends various tRNA genes in Saccharomyces cerevisiae genome. Although most sigma elements characterized to date are isolated insertions, few occur relatively closely spaced. One these direct repeat separated by an internal domain 4.7 kilobase length. Not only does this structure resemble composite transposable element, but regions and intervening homologous conserved retroviruses retrotransposons yeast other organisms. Two features suggest that DNA transposed concerted event: one two associated with gene, outside flanked 5-base repeats usually flank individual insertions. Examination genomic from five laboratory strains indicates present four copies per haploid genome location differs strain strain. In addition, Northern blot analysis showed presence 5.2 poly(A) transcript hybridizes both domain-specific probes. The existence may new ways consider mechanisms select their targets.