K12-biotinylated histone H4 marks heterochromatin in human lymphoblastoma cells

GABRIELA CAMPOREALE, ANNA M. OOMMEN, JACOB B. GRIFFIN, GAUTAM SARATH, JANOS ZEMPLENI

JOURNAL OF NUTRITIONAL BIOCHEMISTRY

Año: 2007 vol. 18 p. 760 - 768

0955-2863

Covalent modifications of histones play crucial roles in chromatin structure and genomic stability. Recently, we reported a novel 12 modification of histones: biotinylation of lysine residues. Here we provide evidence that K12-biotinylated histone H4 (K12Bio H4) maps 13 specifically to both heterochromatin (alpha satellite repeats in pericentromeric regions) and transcriptionally repressed chromatin (g-G globin 14 and interleukin-2) in human lymphoblastoma cells. The abundance of K12Bio H4 in these regions was similar to that of K9-dimethylated 15 histone H3, a known marker for heterochromatin. Likewise, K8-biotinylated histone H4 (K8Bio H4) mapped to heterochromatin, but the 16 relative enrichment was smaller compared with K12Bio H4. Stimulation of interleukin-2 transcriptional activity with phorbol-12-myristate-17 13-acetate and phytohemagglutinin caused a rapid depletion of K12Bio H4 in the gene promoter. These data are consistent with a novel role 18 for biotin in chromatin structure and transcriptional activity of genes.