ADP-ribosylation of trout testis chromosomal proteins: distribution of ADP-ribosylated proteins among DNase I-sensitive and -resistant chromatin domains

I have analyzed the distribution of adenosine diphosphoribose groups in acid-soluble proteins from trout testis chromatin. The results indicate that the inner nucleosomal histones 2A and 2B, together with H1 and the high-mobility-group (HMG) proteins HMG-T and H6, can be ADP-ribosylated when purified trout testis nuclei are incubated with labeled NAD⁺. I have also examined the partition of ADP-ribosylated histones and HMG proteins among DNase I-sensitive (transcriptionally competent) and DNase I-resistant (transcriptionally inert) domains of trout testis chromatin. The data show a preferential localization of ADP-ribosylated HMG proteins in DNase I-sensitive chromatin.