HSV HI-JACKS TUMOR SUPPRESSOR GENESHerpes simplex virus (HSV) may recruit two tumor suppressorgene proteins to carry out its own replication, an article intoday's issue of Nature reports.
Scientists at the Imperial Cancer Research Fund (ICRF) in SouthMimms, U.K., near London, found both p53 and RB-1 in thereplication complex that makes copies of HSV DNA.
Normal tumor suppressor genes control cell growth, whereasdefective forms of the genes lead to cancer. Defects in RB-1lead to retinoblastoma, a form of eye cancer. p53 defects areassociated with a number of tumors, including breast cancer.Several companies, including Applied bioTechnology Inc.,Bristol-Myers Squibb Co., Cell Genesys Inc., Gene Therapy Inc.,Hoffmann-La Roche, Oncogene Sciences, Oncor Inc. and ViageneInc., are developing diagnostics and therapeutics based ontumor suppressor genes.
The ICRF team proposes that HSV proteins take over theinfected cell's replication machinery by inactivating p53 andRB-1. Understanding the mechanisms involved may elucidatethe roles and cellular targets of these tumor suppressor genes.
Previous studies have shown that HSV is not unique in usingthis mechanism to inactivate tumor suppressor genes. CertainSV40, adenovirus and papillomavirus proteins also bind to andderegulate p53 and RB-1. -- Carol Talkington Verser, Ph.D.
POSSIBLE NEW TREATMENT FOR PARKINSON'SAlso in today's Nature, Schering AG researchers report thatinternal or environmental poisons may cause Parkinson'sdisease, a neurodegenerative disorder characterized bytremors. They also suggest a way to stop the toxins fromdestroying nerve cells.
Lechoslaw Turski and his colleagues in Berlin inducedParkinson-like symptoms in rats by treating them with 1-methyl-4-phenyl-pyridinium ion (MPP+), a neurotoxin thatbinds to NMDA (N-methyl-D-aspartate) receptors in the brain.Excitatory amino acids (EAAs) glutamate and aspartate alsoexert their neurotoxic effects by binding to NMDA receptors.
Certain EAA or NMDA antagonists were shown to block MPP+'snerve-killing effects. The results suggest that EAAs may belinked to Parkinson's disease and that EAA antagonists mightoffer a means to treat Parkinsonism.
Companies developing EAA or NMDA receptor antagonists totreat neurological disorders are Cambridge NeuroscienceResearch Inc., Allelix Biopharmaceuticals Inc., CortexPharmaceuticals Inc., Eli Lilly & Co., Marion Merrell Dow Inc.and Sibia Inc. -- CTV
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