SLBP (stem-loop binding protein) is an RNA-binding protein essential for replication-dependent histone mRNA processing and cell cycle regulation. Functionally, SLBP binds the conserved stem-loop structure at the 3' end of canonical histone pre-mRNAs and stabilizes the U7 snRNP complex, enabling endonucleolytic cleavage and 3'-end processing 1. Unlike other eukaryotic mRNAs, histone transcripts lack poly(A) tails and depend on SLBP for this specialized processing pathway. SLBP additionally mediates nuclear export and translation of mature histone mRNA by interacting with translation initiation factors through SLIP1-binding motifs 2. The protein stabilizes histone mRNA levels and couples histone synthesis to DNA replication 3. Loss of SLBP function triggers aberrant polyadenylation of histone mRNAs, causing genomic instability and cell cycle disruption 1. Clinically, SLBP depletion is implicated in carcinogenesis: heavy metal carcinogens (arsenic, nickel) and bisphenols induce SLBP degradation, leading to histone mRNA misprocessing and malignant transformation 4. Conversely, SLBP overexpression drives lung adenocarcinoma progression by inhibiting ferroptosis via SLC7A11 and reprogramming glutamine metabolism through FADS2 interaction 5. SLBP is subject to cell-cycle-dependent degradation by Cyclin F and FEM1-containing ubiquitin ligase complexes 6, ensuring proper temporal regulation of histone gene expression.