Chromatin from transcribed genes contains HMG17 only downstream from the starting point of transcription

Monoclonal antibodies specific for the non-histone chromosomal protein HMG17 were used to isolate oligonucleosomes from the transcriptionally active chromatin of chicken liver and oviduct. The distribution of HMG17 with respect to the coding region of three genes was analyzed in these oligonucleosomes by employing two independent experimental approaches. In the vitellogenin II gene (active in liver) and the lysozyme and ovalbumin genes (active in oviduct) HMG17 was found only downstream from the respective starting points of transcription. The transition from HMG17-free to HMG17-containing chromatin is located at the transcription start. This directly demonstrates that the distribution of an abundant nuclear protein correlates with the observation of moderate DNase I-sensitivity in upstream regions and of high sensitivity in the coding regions of active genes.