Syntenic lncRNAs exhibit DNA regulatory functions with sequence evolution

Syntenic long non-coding RNAs (lncRNAs) often show limited sequence conservation across species, prompting concern in the field. This study delves into functional signatures of syntenic lncRNAs between humans and zebrafish. Syntenic lncRNAs have high expression in zebrafish and ∼90% near protein-coding genes in sense or antisense orientation. During early zebrafish development and human embryonic stem cells (H1-hESC), are enriched with cis-regulatory repressor signatures, influencing development-associated genes. In later zebrafish developmental stages and specific human cell lines, these lncRNAs serve as enhancers or transcription-start-sites(TSS) for protein-coding. Analysis of Transposable Elements (TEs) in syntenic lncRNA sequence divergence unveils intriguing patterns, human lncRNAs show enrichment in simple repeat elements, while zebrafish counterparts exhibit LTR element enrichment. This sequence evolution, possibly stemming from post-rearrangement mutations, enhances DNA elements or cis-regulatory functions. It may also contribute to vertebrate innovation by creating novel TF binding sites within the locus. This study sheds light on the conserved functionality of syntenic lncRNAs through DNA elements, emphasizing their role across species despite sequence divergence.