Long-terminal repeat (LTR) retrotransposons typically contain gag, pol, or gag–pol, and in some case env genes.  The gag gene encodes structural proteins of the virus particle. The pol gene encodes a polyprotein consisting of an aspartic proteinase (AP), a reverse transcriptase (RT), an RNase H (RH), and an integrase (INT).

In this work, Chengdu Institute of Biology Prof.TAN Hong's team used data mining of the Botrytis cinerea genomic sequence and a molecular approach to identify Boty-like LTR retrotransposons in B. cinerea containing an antisense gene (brtn) between pol and the 3′-LTR. Researchers demonstrated that reverse transcriptase PCR (RT-PCR) revealed that some brtn-like genes could be expressed, at least in B. cinerea T4.

Researchers  conducted BLAST comparisons and conserved-domain analysis, but the function of putative BRTN is presently unknown. Boty-like LTR retrotransposons in Sclerotinia sclerotiorum, called ScscLRET and containing brtn homologs at positions similar to brtn, were detected by homology searches and data mining of the S. sclerotiorum 1980 genomic sequence. Thus, this study demonstrated that some fungal LTR retrotransposons contain additional antisense genes.

Chinese Academy of Sciences and  Hi-Tech Research and Development Program (863) of China have supported TAN's project for a long time. And more details have been published in VIROLOGY .