The 6-kilobase c-erbB2 promoter contains positive and negative regulatory elements functional in human mammary cell lines.

A 6-kilobase fragment extending at the 5'-end of the c-erbB2 protooncogene was isolated from a normal human lymphocyte genomic DNA library. The full-length fragment and five subfragments with identical 3'-ends were obtained by progressive unidirectional deletion from the 5'-end and were cloned in front of the luciferase reporter gene. The hybrid genes were analyzed for transcriptional activity in human mammary cell lines synthesizing low (HBL-100 and T-47D), moderate (MDA-MB-453), or high (BT-474) amounts of the c-erbB2 mRNA and were also analyzed in HeLa cells.

Interactions of CF1, the coupling factor of photophosphorylations, with chloroplast lipids. Monolayers studies.

Surface pressure and surface potential of monolayers at a water-air interface show no polar interactions between the chloroplast total lipids and the polar protein CF1. The two components are perfectly miscible in mixed monolayers. It follows that CF1 interacts with the hydrophobic parts of the lipid molecules and that, in vivo, CF1 could penetrate in the hydrophobic core of the membranes.

Binding of the chloroplast coupling factor CF to lipid vesicles.

The binding of the chloroplast coupling factor CF to lipid vesicles was analyzed by gel filtration. CF can be bound to vesicles made of chloroplast lipids but not of lecithin. The presence in the vesicle walls of a proteolipid subunit of the hydrophobic component of the coupling factor increases the binding of CF.