Long non-coding RNAs (lncRNAs) are widely expressed and play key roles in gene regulation. Recent studies have begun to uncover how lncRNAs differ in biogenesis from mRNAs and how their subcellular localization and functions are linked. Depending on their localization and interactions with DNA, RNA, and proteins, lncRNAs can modulate chromatin function, regulate nuclear bodies, alter mRNA stability and translation, and interfere with signaling pathways. These functions affect gene expression in various biological contexts, including neuronal disorders, immune responses, and cancer. Tissue-specific and condition-specific expression patterns suggest that lncRNAs are potential biomarkers and may be targeted clinically. This review discusses the mechanisms of lncRNA biogenesis, localization, and functions in gene regulation, as well as their potential therapeutic applications. LncRNAs are transcribed by RNA polymerase II and often have 5'-end m7G caps and 3'-end poly(A) tails, similar to mRNAs. However, their biogenesis, processing, and export differ from mRNAs. Some lncRNAs are retained in the nucleus, while others are spliced and exported to the cytoplasm. The nuclear retention of lncRNAs is influenced by sequence motifs and factors that recruit proteins like U1 snRNP and hnRNPK. Some lncRNAs are sorted into mitochondria or exosomes, and their functions can involve structural or regulatory roles in mRNA life cycles, including splicing, turnover, and translation. LncRNAs regulate gene expression at multiple levels, including chromatin structure and function, transcription of neighboring and distant genes, and RNA splicing, stability, and translation. They also participate in the formation and regulation of organelles and nuclear condensates. LncRNAs can interact with DNA to form structures like R-loops, which can activate or inhibit gene expression. Some lncRNAs, such as XIST, are involved in X chromosome inactivation, while others, like ANRIL, regulate gene expression through interactions with chromatin modifiers. LncRNAs can also regulate gene expression by interfering with the transcription machinery, altering the recruitment of transcription factors or Pol II, and modifying histone modifications. They can act as decoys for chromatin modifiers or as regulators of chromatin looping. Some lncRNAs, such as SWINGN, promote the interaction between chromatin remodeling complexes and gene promoters, contributing to their pro-oncogenic roles. Other lncRNAs, like ELEANORs, help form genomic domains that regulate gene expression. LncRNAs are involved in various biological processes, including DNA damage response, genome integrity, and developmental regulation. They can activate or repress gene expression through interactions with chromatin, transcription factors, and other regulatory elements. The functions of lncRNAs are diverse, and their regulation is complex, involving multiple layers of controlLong non-coding RNAs (lncRNAs) are widely expressed and play key roles in gene regulation. Recent studies have begun to uncover how lncRNAs differ in biogenesis from mRNAs and how their subcellular localization and functions are linked. Depending on their localization and interactions with DNA, RNA, and proteins, lncRNAs can modulate chromatin function, regulate nuclear bodies, alter mRNA stability and translation, and interfere with signaling pathways. These functions affect gene expression in various biological contexts, including neuronal disorders, immune responses, and cancer. Tissue-specific and condition-specific expression patterns suggest that lncRNAs are potential biomarkers and may be targeted clinically. This review discusses the mechanisms of lncRNA biogenesis, localization, and functions in gene regulation, as well as their potential therapeutic applications. LncRNAs are transcribed by RNA polymerase II and often have 5'-end m7G caps and 3'-end poly(A) tails, similar to mRNAs. However, their biogenesis, processing, and export differ from mRNAs. Some lncRNAs are retained in the nucleus, while others are spliced and exported to the cytoplasm. The nuclear retention of lncRNAs is influenced by sequence motifs and factors that recruit proteins like U1 snRNP and hnRNPK. Some lncRNAs are sorted into mitochondria or exosomes, and their functions can involve structural or regulatory roles in mRNA life cycles, including splicing, turnover, and translation. LncRNAs regulate gene expression at multiple levels, including chromatin structure and function, transcription of neighboring and distant genes, and RNA splicing, stability, and translation. They also participate in the formation and regulation of organelles and nuclear condensates. LncRNAs can interact with DNA to form structures like R-loops, which can activate or inhibit gene expression. Some lncRNAs, such as XIST, are involved in X chromosome inactivation, while others, like ANRIL, regulate gene expression through interactions with chromatin modifiers. LncRNAs can also regulate gene expression by interfering with the transcription machinery, altering the recruitment of transcription factors or Pol II, and modifying histone modifications. They can act as decoys for chromatin modifiers or as regulators of chromatin looping. Some lncRNAs, such as SWINGN, promote the interaction between chromatin remodeling complexes and gene promoters, contributing to their pro-oncogenic roles. Other lncRNAs, like ELEANORs, help form genomic domains that regulate gene expression. LncRNAs are involved in various biological processes, including DNA damage response, genome integrity, and developmental regulation. They can activate or repress gene expression through interactions with chromatin, transcription factors, and other regulatory elements. The functions of lncRNAs are diverse, and their regulation is complex, involving multiple layers of control