Tdd-3, a tRNA gene-associated poly(A) retrotransposon from Dictyostelium discoideum.
The full-length 5218-bp sequence of the mobile genetic element Tdd-3 from Dictyostelium discoideum is described. Tdd-3 encodes two overlapping open reading frames (ORFs) flanked by non-redundant, untranslated regions. The deduced amino acid sequence of ORF2 is homologous to reverse transcriptases (RTs) encoded by the class of poly(A) retrotransposons. ORF2 also encodes a putative protein domain related to the family of apurinic/apyrimidinic (AP) endonucleases, whose retroelement-encoded homologs have recently been proposed to represent the integrase function of poly(A) retrotransposons. Comparison of several genomic Tdd-3 copies revealed that element insertion is orientation specific and occurs about 100 bp downstream of tRNA genes in the D. discoideum genome. These properties of Tdd-3 suggest that the element is a tRNA gene-associated poly(A) retroelement present in the D. discoideum genome. Analysis of several cloned cDNAs derived from Tdd-3-specific plus strand RNAs indicate that the element is transcribed and polyadenylated during the growth of D. discoideum cells.
Winckler
T
T
Institut für Pharmazeutische Biologie, Universität Frankfurt/M. (Biozentrum), Germany. Winckler@em.uni-frankfurt.de
Tschepke
C
C
de Hostos
E L
EL
Jendretzke
A
A
Dingermann
T
T
D000818:Animals; D004271:DNA, Fungal / Q000235:genetics*; D004023:Dictyostelium / Q000235:genetics*; D012343:RNA, Transfer / Q000235:genetics; D018626:Retroelements / Q000235:genetics*
D004271:DNA, Fungal; D018626:Retroelements; D012343:RNA, Transfer