Residual DNA-bound proteins are a source of in vitro transcription inhibitor peptides.
Enzymatic breakdown of residual proteins occurs at mild alkaline pH (pH optimum 8.5) as monitored by using radioiodinated, purified genomic DNA from calf thymus. These DNA fibers also possess a differential ability to hydrolyze added exogenous small and linker histones. The results described argue strongly that a putative protease activity, co-purified with DNA, is the source of short chain peptides which inhibit transcription in vitro3. Therefore, we propose that RNA repressor peptides must be of higher molecular weight than previously reported.
Venanzi
F M
FM
Department of Cell Biology, University of Camerino, Italy.
D000818:Animals; D002417:Cattle; D002843:Chromatin / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D007457:Iodine Radioisotopes; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism; D010455:Peptides / Q000037:antagonists & inhibitors*; D014157:Transcription Factors / Q000037:antagonists & inhibitors*
D002843:Chromatin; D004268:DNA-Binding Proteins; D006657:Histones; D007457:Iodine Radioisotopes; D010455:Peptides; D014157:Transcription Factors; D010447:Peptide Hydrolases