Structure of the chicken Ovex1 endogenous retrovirus. (A) Genomic position of Ovex1. LOC422925 and LOC422926 (May 2006 Gallus gallus v 2.1, galGal3 genome draft assembly) are indicated. The SSH-cloned OG43 cDNA fragment is shown. (B) Published ESTs (8-26-2007). (C) Overlapping RT-PCR fragments amplified from ovarian RNA used for cDNA sequencing. (D) Determination of mRNA ends by 5' and 3'RACE PCR (primers used and direction of the synthesis). (E) ORF map. (F) Transcription profile. Two types of mRNA are produced: a mRNA corresponding to the complete genomic sequence and a mRNA with one splicing event. Position of the splice donor and acceptor sites relative to the transcription start site is indicated between brackets, and the spliced out domain represented by a dotted line. Untranslated regions are shown in gray and the 5' and 3' imperfect repeats marked by (R). Encoded protein domains are indicated. Primer sequences are given in additional file 9 (Table S1, Primers and PCR conditions).