Fulminant Wilson's disease requiring liver transplantation in one monozygotic twin despite identical genetic mutation.

Acute decompensated Wilson's disease (WD) that presents as fulminant hepatic failure carries significant mortality without hepatic replacement. The abnormal gene implicated in WD, ATP7B, has been mapped to chromosome 13, and leads to decreased passage of copper from hepatocytes to bile. Excess copper accumulation exceeds hepatocyte storage capacity resulting in intracellular necrosis, apoptosis and cell death in various organs of the body. The hepatic injury induced by the abnormal accumulation of copper in WD has variable presentation such as acute hepatitis, rapid hepatic deterioration resembling fulminant hepatic failure, or as progressive chronic liver disease in the form of chronic active hepatitis or cirrhosis. There are reports in the literature describing monozygotic (identical) twins with similar hepatic progression requiring liver transplantation, however, with different neurological outcome after transplant. We report a case of one monozygotic twin presenting with acute liver failure requiring emergent liver transplantation while the other twin presented with mild liver disease, when both shared an identical genetic mutation.

Integrations of the hepatitis B virus (HBV) and human papillomavirus (HPV) into the human telomerase reverse transcriptase (hTERT) gene in liver and cervical cancers.

Chronic infections with the hepatitis B virus (HBV) and high-risk human papillomaviruses (HPVs) are important risk factors for hepatocellular carcinoma (HCC) and cervical cancer (CC), respectively. HBV and HPV are DNA viruses that almost invariably integrate into the host genome in invasive tumors. The viral integration sites occur throughout the genome, leading to the presumption that there are no preferred sites of integration. A number of viral integrations have been shown to occur within the vicinity of important cancer-related genes. In studies of HBV-induced HCC and HPV-induced CC, we have identified two HBV and three HPV integrations into the human telomerase reverse transcriptase (hTERT) gene. Detailed characterization of the integrations revealed that four integrations occurred within the hTERT promoter and upstream region and the fifth integration occurred in intron 3 of the hTERT gene. None of the integrations altered the hTERT coding sequence and all resulted in juxtaposition of viral enhancers near hTERT, with potential activation of hTERT expression. Our work supports the hypothesis that the sites of oncogenic viral integration are nonrandom and that genes at the sites of viral integration may play important roles in carcinogenesis.

Combinatorial selection of a small RNA that induces amplification of IncFII plasmids in Escherichia coli.

Cellular RNAs play fundamental roles as genetic messages, structural components and, in some cases, as catalytic agents. The ability to create vast combinatorial libraries of random RNA sequences has previously been exploited in vitro to identify RNA aptamers with desirable binding specificities, and to isolate RNAs with novel catalytic properties. Despite the advantages of in vitro selections from RNA libraries, there is no way to predict if the identified RNAs can function in living cells. We are therefore exploring random RNA expression libraries in Escherichia coli to search for small RNAs with novel functions. Here we describe selections that identified a small RNA (approximately 260 nucleotides) capable of altering the copy-number control circuitry of IncFII plasmids. The novel RNA appears to function by annealing to a region of the mRNA encoding the plasmid replicator protein. The resulting RNA-RNA hybrid permits translation of the replicator protein, but blocks base-pairing with a natural negative regulatory RNA. Implications of this in vivo selection strategy are discussed.

Quantitating oligonucleotide affinities for duplex DNA: footprinting vs electrophoretic mobility shift assays.

Determining the affinities of oligonucleotides for duplex DNA is an important analytical problem that arises during the design of potential gene repressors based on triple helix recognition. Quantitative DNa-seI footprinting assays (QDFA) offer a rigorous technique for this purpose. Electrophoretic mobility shift assays (EMSA) have proven to be simpler and more rapid. Although EMSA can separate triplex and duplex complexes, there is concern that this technique does not afford as rigorous an equilibrium measurement as is provided by QDFA. We show that QDFA and EMSA techniques provide Kd estimates that agree within one order of magnitude under common experimental conditions. Agreement is best in buffers with low concentrations of monovalent cations. Surprisingly, EMSA appears to slightly overestimate triplex stabilities relative to QDFA in the presence of physiological concentrations of monovalent cations (100 mM). Under these conditions, agreement between the techniques can be improved by quenching EMSA samples with excess unlabeled competitor duplex just prior to gel loading. The data suggest that EMSA can provide results in reasonable agreement with QDFA and offer some insight into sources of deviation between the two methods.