Low abundance of wild-type biotinidase and holocarboxylase synthetase decreases biotinylation of histones

GABRIELA CAMPOREALE, YOICHI SUZUKI, JOEL C. EISSENBERG, JANOS ZEMPLENI

San Diego, CA - EEUU

Conferencia; Federation of American Societies for Experimental Biology (FASEB); 2005

DNA-histone interactions may be affected by a variety of histone modifications, possibly including biotinylation. Both biotinidase (BTD) and holocarboxylase synthetase (HCS) mediate biotinylation of histones. Here we tested the hypothesis that low abundance of wild-type BTD and HCS decreases histone biotinylation. The following experimental models were generated: a) cells expressing mutant HCS: fibroblasts from patients with HCS deficiency; and b) cells with low abundance of wild-type BTD and HCS: Drosophila melanogaster and human lymphoid cells treated with siRNA. Biotinylated histones were quantified by Western blot analysis using polyclonal antibodies to K8-biotinylated histone H4 and K12-biotinylated histone H4. Low abundance of wild-type HCS was associated with a low abundance of biotinylated histones. For example, biotinylation of histone H4 at K12 decreased by 80% in HCS mutant fibroblasts compared with normal controls. Preliminary data suggest that BTD deficiency might also affect histone biotinylation. We conclude that the abundance of K12-biotinylated histone H4 depends on HCS and, perhaps, on BTD in human cells. We speculate that patients carrying BTD or HCS mutations might be at increased risk for developing abnormal DNA structures.