No abstract

A recombinant histone (NLS-H1) containing both the SV40 large T antigen nuclear localization signal and the carboxy-terminal domain of human histone H1(0) was produced in bacteria. NLS-H1-plasmid DNA complexes, in the presence of chloroquine, mediated reporter gene transfer into cultured cells with similar efficiencies as plasmid DNA-cationic lipid (lipofectin) complexes. NIH-3T3 or COS-7 cells transfected with NLS-H1-plasmid DNA-lipofectin complexes expressed at least 20 times more luciferase or had at least 2.5 times more beta-galactosidase-positive cells than those transfected with plasmid DNA-lipofectin complexes. Foreign gene expression was also improved by other DNA-binding proteins and cationic lipid formulations, yet the greatest enhancement was obtained with complexes containing either NLS-H1 or calf thymus histone H1. Histone H1-plasmid DNA-lipofectin complexes were internalized by a greater number of cells than plasmid DNA-lipofectin complexes.

Postmortem storage of bovine psoas major muscle resulted in almost complete degradation of nebulin by 48 hr; however, some intact titin was still observed after 2 wk storage at 4°C. The percentage of myofibrils having four anti&in bands per sarcomere (immunofluorescence microscopy) was less than 1% at 45 min but increased to 65% at 48 hr after death and remained stable thereafter. A similar four band pattern was seen in frozen sections of whole muscle at 48 hr or more postmortem. The time course of nebulin degradation appeared to correlate with the titin two to four band transition.

No abstract

Expression of Becker-like and full-length human dystrophins was stable for at least 6 months in mdx mouse muscle following intramuscular plasmid DNA injection. Intramuscular injection of a single plasmid DNA encoding both luciferase and dystrophin resulted in stable luciferase expression for at least 2 months in mdx muscle, whereas injection of plasmid DNA encoding only luciferase did not result in stable luciferase expression. These results suggest that expression of either full-length or Becker-like dystrophins protects mdx mouse myofibers from degeneration.