Ovine LncRSFD1 Mined from RNA-Seq: Identification, Expression Profile, Promotion of Preadipocyte Differentiation, Promoter Activity, and Its Polymorphisms Related to Phenotypic Traits

Tail fat is essential for sheep survival in extreme environments, yet its significance is often overlooked, leading to the decline of fat-tailed breeds. This study identified a novel lncRNA, lncRSFD1 (TCONS_00054953), through transcriptome sequencing, showing differential expression in the tail adipose tissues of Lanzhou Fat-Tailed (LFT) sheep and Tibetan (TS) sheep. Highly expressed in adipose tissues, lncRSFD1 inhibits preadipocyte proliferation and promotes 3T3-L1 differentiation, suggesting its role in regulating fat deposition. Located in both the cytoplasm and nucleus, lncRSFD1 targets the neighboring gene PDE4DIP and may function as a molecular sponge for conserved miRNAs, including oar-miR-30a-3p, oar-miR-329b-5p, and oar-miR-431, which are known to influence fat and muscle-related physiological processes. Moreover, the core promoter of lncRSFD1 (-2607 bp to -1776 bp) harbors four SNPs (g.-2429G>A, g.-2030T>C, g.-2016C>T, g.-2015G>A) significantly associated with growth traits such as body height in Guiqian Semi-Fine Wool (GSFW) sheep. These findings suggest lncRSFD1 plays a key role in fat deposition and growth regulation, offering new insights into the molecular mechanisms of lncRNAs in sheep. It provides a potential target for genetic improvement and molecular breeding to enhance fat deposition and adaptability in sheep breeds.