Transcriptional inhibitory role of the tail domains of histone (H3 x H4)2 tetramers.

Histone-DNA templates for bacteriophage T7 RNA polymerase were assembled from a plasmid containing a promoter and a terminator for this polymerase, (H3 x H4)2 tetramers deprived of their tail domains, and H2A x H2B dimers. Histone (H3 x H4)2 tetramers lacking their terminal domains were obtained from trypsin-digested nucleosomal cores. The oligonucleosomal templates containing (H3 x H4)2 tetramers lacking their tail domains, like the control templates with intact core histone octamers, protect approximately 146 base pairs of DNA against micrococcal nuclease digestion.

Transcriptional properties of oligonucleosomal templates containing acetylated (H3-H4)2 tetramers.

Direct chemical acetylation of an oligonucleosomal template for bacteriophage T7 RNA polymerase is accompanied by a substantial increase in its capability to support RNA synthesis. The template was assembled from a plasmid, containing a promoter and a terminator for T7 RNA polymerase, plus one (H3-H4)2 tetramer and two H2A.H2B dimers for each 200 base pairs of DNA.

Modulation of glycogen phosphorylase activity and fructose 2,6-bisphosphate levels by glibenclamide and meglitinide in isolated rat hepatocytes: a comparative study.

The influence of glibenclamide and meglitinide, or 4-[2-(5-chloro-2-methoxybenzamide)ethyl]-benzoic acid, a compound similar to the nonsulfonylurea moiety of glibenclamide, on glycogen phosphorylase a activity, fructose 2,6-bisphosphate (F-2,6-P2) level, and cytoplasmic free-Ca2+ concentration has been studied in isolated rat hepatocytes. Both glibenclamide and meglitinide caused a transient and dose-dependent activation of glycogen phosphorylase, with half-maximal effects corresponding to 3.7 +/- 1.

Acetylation of histone H2A.H2B dimers facilitates transcription.

Histone-DNA templates for bacteriophage T7 RNA polymerase were assembled from a plasmid containing a promoter and a terminator for T7 RNA polymerase, intact (H3.H4)2 tetramers, and either untreated or chemically acetylated H2A.H2B dimers.

Efficient transcription of a DNA template associated with histone (H3.H4)2 tetramers.

A histone-DNA transcription template has been assembled, by dialysis against decreasing salt concentrations, from pGEMEX-1 (4 kilobases), a plasmid containing a promoter for bacteriophage T7 RNA polymerase, and from isolated histone (H3.H4)2 tetramers. Electron microscopy after psoralen cross-linking shows that each histone tetramer protects approximately 80 base pairs of DNA from psoralen action and that, under the employed conditions, an average of 15 tetramer particles are assembled per DNA molecule.