RESUMO
To study the expression of extrahepatic apolipoprotein E (apoE) under hypercholesterolemic conditions, apoE mRNA levels were evaluated in 14 tissues of rabbits fed on a cholesterol rich diet and compared to age-matched control animals. In hypercholesterolemic rabbits apoE expression was significantly induced in adipose tissue, adrenals, aorta, lung and spleen. The increase in apoE mRNA levels in lung and spleen was associated with the presence of cholesterol-loaded macrophages. These cells were found to express high levels of apoE mRNA as demonstrated by in situ mRNA hybridization. Our results suggest that extrahepatic tissues would be partially responsible for the rise in serum apoE levels detected under hypercholesterolemic conditions.
Assuntos
Apolipoproteínas E/biossíntese , Colesterol/metabolismo , Hipercolesterolemia/metabolismo , Macrófagos/metabolismo , Tecido Adiposo/metabolismo , Glândulas Suprarrenais/metabolismo , Animais , Aorta/metabolismo , Feminino , Imunofluorescência , Hibridização In Situ , Pulmão/metabolismo , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , Coelhos , Baço/metabolismo , Distribuição TecidualRESUMO
A variety of functions codified by both the host chromosome and the plasmid genome are necessary for plasmid replication. We have found that dna B and dna F are essential for replication of both types of plasmids: R144 and Sa which have a restricted control of replication, and R6K with a relaxed control; on the other hand plasmids belonging to the first group absolutely depend on dna A and dna E gene products. Plasmid Sa, which shares with the 1st group a restricted control of replication but appears on a number of intermediate copies, shows a partial requirement to the dna A gene product. Location studies of plasmid-coded genes, involved in the replications of plasmids, were carried out in plasmid pSC102, a derivative of the resistance plasmic R6-5. All the genes required for replication are contained into a DNA segment which consists of two Pst I fragments: P-4 and P-6. The origin of replication On V is not itself sufficient for autonomous replication but needs in addition the presence of the Rep A gene. Genes responsible for copy control and incompatibility Cop/Inc are located on fragment P-6, i.e. they are physically distinct from Ori V. This indicates that the origin of replication is not responsible for, although may participate in, the incompatibility phenomenon.
