DNA-binding properties of the antibody specific for the Dewar photoproduct of thymidylyl-(3-5')-thymidine.

A monoclonal antibody (DEM-1) specific for the Dewar photoproduct is used for detection and quantification of photolesions in DNA. To help understand the molecular recognition of damaged DNA by the antibody protein, we have cloned and sequenced the variable region genes of DEM-1. We have also prepared Fab fragments of DEM-1 (DEM1Fab), and synthesized two kinds of 3'-biotinylated oligonucleotides of different lengths containing a central Dewar photoproduct of TpT to analyze the effects of the antigen size on the binding rates by means of surface plasmon resonance (SPR).

Oxidized but not acetylated low-density lipoprotein reduces preproinsulin mRNA expression and secretion of insulin from HIT-T15 cells.

We examined the effect of oxidized low-density lipoprotein (oxLDL) on the insulin secretion in the culture of HIT-T15 cell line, an islet beta-cell line derived from a hamster pancreatic tumor. In order to check the uptake of modified LDL by HIT-T15 cells, we prepared DiI-labeled native LDL (nLDL), acetylated LDL (AcLDL), and oxLDL. After the addition of each LDL into the cultures of HIT-T15 cells, fluorescence microscopic study was done.