Cloning of a mammalian transcriptional activator that binds unmethylated CpG motifs and shares a CXXC domain with DNA methyltransferase, human trithorax, and methyl-CpG binding domain protein 1.

Ligand screening was utilized to isolate a human cDNA that encodes a novel CpG binding protein, human CpG binding protein (hCGBP). This factor contains three cysteine-rich domains, two of which exhibit homology to the plant homeodomain finger domain. A third cysteine-rich domain conforms to the CXXC motif identified in DNA methyltransferase, human trithorax, and methyl-CpG binding domain protein 1. A fragment of hCGBP that contains the CXXC domain binds to an oligonucleotide probe containing a single CpG site, and this complex is disrupted by distinct oligonucleotide competitors that also contain a CpG motif(s). However, hCGBP fails to bind oligonucleotides in which the CpG motif is either mutated or methylated, and it does not bind to single-stranded DNA or RNA probes. Furthermore, the introduction of a CpG dinucleotide into an unrelated oligonucleotide sequence is sufficient to produce a binding site for hCGBP. Native hCGBP is detected as an 88-kDa protein by Western analysis and is ubiquitously expressed. The DNA-binding activity of native hCGBP is apparent in electrophoretic mobility shift assays, and hCGBP trans-activates promoters that contain CpG motifs but not promoters in which the CpG is ablated. These data indicate that hCGBP is a transcriptional activator that recognizes unmethylated CpG dinucleotides, suggesting a role in modulating the expression of genes located within CpG islands.

Food cues and perceptual distortion of the female body: implications for food avoidance in the early dynamics of anorexia nervosa.

The present studies concerned a perceptual mechanism that could partially explain the anorexic's severe eating restraint despite continuing hunger. If a woman values a thin body, unrealistic perception of food's fattening effects should increase the aversiveness of ingesting food and foster restraint in eating. The first study considered the perceived thinness/fatness of women's bodies without and with food cues present. College women who (1) shared the stress-generating personality characteristics of anorexics (AP); and (2) judged models as fatter after food cues were introduced (enhancers) reported more stress than AP non-enhancers; no effect of enhancement upon stress was observed in controls. This moderator effect was replicated in a second study. Thus, women with the personality characteristics and high stress that put them at-risk for anorexia also displayed the perceptual distortion involved in the proposed mechanism. Self-ratings verified the same perceptual mechanism in the high-stress AP woman's perception of her own body.