Multiacetylated forms of H4 are found in a putative transcriptionally competent chromatin fraction from trout testis.

We have examined the distribution of acetylated histones derived from various trout testis chromatin fractions of different composition. Our results indicate that a chromatin fraction, preferentially solubilized by micrococcal nuclease, containing the bulk of the HMG proteins and similar to a fraction released from intact trout nuclei and previously shown to be enriched in transcribed DNA sequences also possesses high levels of multiacetylated species of H4. Histones 2A, 2B and 3 are also acetylated in this particular chromatin fraction. Monoacetylated species of the 4 inner nucleosomal histones appear to be characteristic of the nucleohistone portion of trout testis chromatin.