Histone H1.5 (H1.5)

Histone H1.5 is a member of the linker histone H1 family, which binds to DNA at the entry and exit sites on nucleosomes and stabilizes the structure of chromatin by promoting the compaction of chromatin fibers[2][3][4][6]. Unlike the core histones (H2A, H2B, H3, H4) that form the nucleosome core, linker histones like H1.5 do not make up the nucleosome "bead" but instead help organize and stabilize higher-order chromatin structures, influencing processes such as transcription, replication, and splicing[2][3][4]. H1.5 is particularly notable for its relatively long C-terminal domain, which is rich in positively charged residues and confers a higher affinity for chromatin, contributing to its longer residence time in chromatin compared to other H1 subtypes[1]. H1.5 has been shown to play a specific regulatory role in alternative mRNA splicing in differentiated cells by binding over splice sites, affecting exon inclusion and RNA polymerase II pausing at splice junctions[1]. The family of linker histones, including H1.5, mediates chromatin folding and modulates accessibility of DNA to transcription factors and other regulatory proteins, thereby exerting both structural and regulatory control over genetic information in eukaryotic cells[2][3][4][6]. At present, Histone H1.5 is not considered a direct therapeutic target or established biomarker, nor are there known drugs that selectively target it. Altered expression of H1.5 and other H1 variants has been observed in various cancers and during cell differentiation, suggesting possible disease associations but not direct druggability[1][6].

Other names

H1-5H1F5HIST1H1BH1bH1s-3Histone H1aHistone H1bHistone H1s-3H1H1BH1 histone family, member 5histone 1histone cluster 1 H1 family member b