What do linker histones do in chromatin?
Knockout experiments in Tetrahymena show that linker histone H1 is not essential for nuclear assembly or cell viability. These results, together with a series of biochemical and cell biological observations, challenge the existing paradigm that requires linker histones to be a key organizing component of higher-order chromatin structure. The H1 knockouts also reveal a much more subtle role for H1. Instead of acting as a general transcriptional repressor, H1 is found to regulate a limited number of specific genes. Surprisingly, H1 can both activate and repress transcription. We discuss how this architectural protein might accomplish this important regulatory role.
Wolffe
A P
AP
Laboratory of Molecular Embryology, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892-5430, USA. awlme@helix.nih.gov
Khochbin
S
S
Dimitrov
S
S
D000595:Amino Acid Sequence; D000818:Animals; D002843:Chromatin / Q000502:physiology*; D006657:Histones / Q000502:physiology*; D008969:Molecular Sequence Data; D013768:Tetrahymena
D002843:Chromatin; D006657:Histones