Identification and expression analysis of a novel miRNA derived from ERV-E1 LTR in Equus caballus.

This study explored the presence of a new microRNA (miRNA) in horses, derived from the long terminal repeats (LTRs) of the Equus caballus Endogenous Retrovirus (EqERV). This miRNA may influence various horse attributes such as speed and strength. The research revealed that this miRNA exists in different equine tissues and could suggest new research areas for studying the LTR of other EqERV families.

Research Objective and Methodology

• The researchers aimed to identify and analyze a new miRNA linked with EqERV-E1 LTR in Equus caballus or horses. The research sought to expand understanding of the role of EqERV elements, which have been integrated into horse genomes throughout evolution, in influencing key traits like speed, strength, and agility.
• To achieve this, they employed various bioinformatics tools including BLAST2seq for sequence comparison and phylogenetic analysis for understanding evolutionary relationships. LTR sequences were identified and located in the untranslated region (UTR) of mRNAs.

Findings and Analysis

• The researchers identified the new LTR-derived miRNA and registered it in the DDBJ database with the accession number LC383797, also referred to as eca-miR-1804.
• A stem-loop secondary structure was also noticed in the LTR sequences. This structure is significant as it is necessary for the functioning of miRNA.
• Further, they used a quantitative polymerase chain reaction (qPCR) to confirm the presence and expression of eca-miR-1804 and the related miR-1255a, in eight different equine tissues.
• Similar expression patterns were noted for eca-miR-1804 and miR-1255a, suggesting that the LTR-derived miRNA could be functioning in the examined equine tissues.

Implications and Future Research

• The research provides significant insights into the relationship between EqERV-E1 LTR and similar elements. This adds to the understanding of how the LTRs of EqERV might affect the key abilities in horses.
• These findings can also serve as a foundation for further functional studies concerning the LTRs of other EqERV families. Such research can help further unveil the complex gene regulation machinery in horses and its consequences on their various traits.