Naomi F. Campbell, Ph.D.

Research in the Campbell group focuses on environmental genomics.  The long-term goal of the research is to elucidate the mechanism of low-dose ionizing radiation, ultraviolet radiation, and oxidative damage on induced trans-generation genomic instability and DNA methylation.  Ionizing radiation and oxidative damage can interfere with the normal functional of the DNA methylation machinery, which may lead to a change in the DNA and/or chromatin remodeling, and changes in transcription activity.  The methylation of cytosine bases is a natural modification of DNA that does not involve a change in DNA sequence, can affect the remodeling of chromatin, and the level of transcription in a cell.  Chromatin structure plays a major role in the control of gene expression because DNA packaged into chromatin is less accessible to the transcription machinery.   The relaxing of the chromatin structure is necessary for gene expression because the tightly compacted chromatin structure shield a vast number of potential binding sites for transcription activators in eukaryotic cells.  Enhancers and co-activators modulate transcription activity by disrupting the local chromatin structure to expose additional regions to the transcription machinery.  The methyl group of 5-methylcytosine protrudes into the major groove of the DNA double helix and can interfere with binding of proteins that stimulate transcription.  Most genes are located in the CpG islands regions of the genome and the gene sequences contain approximately four-fold as many CpG sequences as the remainder of the genome.