{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n CELF1, also known as CUG‐binding protein 1 (CUGBP1), is a multifunctional RNA‐binding protein that plays pivotal roles in post‐transcriptional gene regulation. Its functions encompass the control of alternative splicing, regulation of mRNA stability/decay, and modulation of translation.\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In the developing heart, for instance, a marked downregulation of CELF1 is associated with coordinated alternative splicing transitions that are essential for proper cardiac maturation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " In contrast, forced or sustained expression of CELF1 in adult cardiac and skeletal muscle recapitulates key features of myotonic dystrophy type 1 (DM1). Aberrant CELF1 activity in these tissues is linked to mis‐splicing events affecting transcripts such as those encoding cardiac troponin T, muscle chloride channels, and other regulatory proteins, which contribute to muscle pathology."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n CELF1 also contributes to translational regulation. For example, it enhances the expression of p21 by directly interacting with GC‐rich elements in the p21 mRNA, thereby promoting cell cycle arrest during myogenic differentiation—a process that is impaired in DM1 muscle cells."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Beyond splicing and translation, CELF1 regulates mRNA decay through binding to GU‐rich elements (GREs) within the 3′ untranslated regions of target mRNAs. By recruiting deadenylase enzymes such as PARN, CELF1 coordinates the turnover of transcripts involved in cell growth, motility, and apoptosis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": " In support of its broad regulatory role, transcriptome‐wide analyses using RIP‐seq in HeLa cells have demonstrated that CELF1 preferentially binds to 3′ UTRs and intronic regions, thereby influencing alternative splicing on a global scale."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Additionally, studies using loss‐of-function models indicate that CELF1 is required for proper cell differentiation. In vivo knockout of CELF1 in mice leads to defects in spermatogenesis, including arrest of spermatid maturation and increased apoptosis, underscoring its significance in reproductive development."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Collectively, these studies demonstrate that CELF1 functions as a central regulator of RNA metabolism—fine‐tuning splicing, decay, and translational processes in a tissue‐ and developmental stage–specific manner. Misregulation of CELF1 contributes to the pathogenesis of neuromuscular disorders such as DM1, highlighting its potential as a therapeutic target.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Auinash Kalsotra, Xinshu Xiao, Amanda J Ward, et al. 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