Hepatitis B virus integration in a cyclin A gene in hepatocellular carcinoma
Article Abstract:
Although hepatitis B virus (HBV) DNA is frequently found integrated into the host genome of liver cancer cells, the significance of this finding is not clear. Now, research has uncovered a human liver cancer cell line in which there is a single copy of HBV DNA in each cancer cell, and the HBV DNA is apparently in the middle of a human gene which normally regulates the reproduction of cells. Using DNA probes, the viral DNA could easily be found within the host genome. The human DNA surrounding the viral DNA was then sequenced, and a strong homology was found with the sequence of the protein cyclin A. Cyclins are a group of proteins which accumulate in a cell as the reproduction cycle progresses, and then disappear rapidly as the cell divides. It has been demonstrated that cyclins are necessary for cell division. Furthermore, cyclins have changed little in the course of evolution, and have remained similar among species as disparate as sea urchins and humans. This conservation through evolution suggests that the protein must be performing a fundamental role in the cell's existence. It might be anticipated that the insertion of viral DNA in the middle of this gene would drastically affect normal cell function. The discovery that, at least in this case, HBV DNA inserts into the cyclin A gene will probably tell us more not only about the hepatitis B virus, but about the function of the cyclins as well. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1990
User Contributions:
Comment about this article or add new information about this topic:
Elevation of auditory thresholds by spontaneous cochlear oscillations
Article Abstract:
Activation of mammalian auditory nerve fibers can be caused by high-intensity spontaneous otoacoustic emissions which result in the reduced capability of neurons to response to other sound. Such loss of hearing capacity is unlike that generated by injury to sensory cells. The rise in excitatory thresholds is due to a high spontaneous activity in neurons induced by spontaneous cochlear oscillations.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1995
User Contributions:
Comment about this article or add new information about this topic:
Direct measurement of intra-cochlear pressure waves
Article Abstract:
The frequency and position dependence of the nonlinear flue pressure are demonstrated, and the results are interpreted with regard to the cochlear travelling wave. Penetration depth is limited and over a range of frequencies at least an octave wide, is independent of frequency.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: GABA regulates synaptic integration of newly generated neurons in the adult brain
- Abstracts: Heritable variation in polyandry in Callosobruchus chinensis. Direct effects of polyandry on female fitness in Callosobruchus chinensis
- Abstracts: E-cadgerin germline mutations in familial gastric cancer. Connexin 26 gene linked to a dominant deafness. Defective myosin VIIA gene responsible for Usher syndrome type 1B
- Abstracts: Bird conservation: more than just chasing the tails. Conserving the migratory birds of Mexico's wetland ecosystems
- Abstracts: Copulation and mate-guarding patterns in polygynous European starlings. Dominance and mating success in male boat-tailed grackles