Nasopharyngeal carcinoma (NPC) occurs with a striking geographic incidence and is endemic in parts of southern China, where it is the major cause of cancer death.
Epstein-Barr virus (EBV) is detected in all cells of the majority of NPC cases regardless of geographic origin.
A small subset of EBV genes is expressed in NPC, including the latent membrane protein (LMP-I).
LMP-I is essential for transformation of B lymphocytes and is considered to be the EBV oncogene.
This analysis of the DNA sequence variation within the LMP-I gene reveals a consensus sequence for a strain, denoted Chinal, which predominates in East Asia where NPC is endemic.
The Chinal strain is characterized by nucleotide changes at 13 loci in the amino terminal portion of the LMP-I gene when compared with the B95-8 prototype, including a point mutation resulting in the loss of an Xhol restriction site.
This strain was present in 9 of 15 NPC biopsy specimens from the endemic region and in 7 of 13 from northern China, where NPC is non-endemic.
A second strain, China2, was detected in 4 of 15 endemic isolates and in 2 of 13 non-endemic isolates ; this strain was characterized by a cluster of 5 nucleotide changes in the amino terminal portion of LMP-I in addition to those seen in Chinal.
It was also marked by distinct changes in the carboxy terminal region of LMP-I including the retention of amino acids 343-352. (...)
Mots-clés Pascal : Carcinome, Nasopharynx, Endémie, Virose, Infection, Virus Epstein Barr, Gammaherpesvirinae, Herpesviridae, Virus, Souche, Variabilité génétique, Phylogenèse, Prévalence, Epidémiologie, Chine, Asie, Homme, ORL pathologie, Pharynx pathologie, Tumeur maligne
Mots-clés Pascal anglais : Carcinoma, Nasopharynx, Endemy, Viral disease, Infection, Epstein Barr virus, Gammaherpesvirinae, Herpesviridae, Virus, Strain, Genetic variability, Phylogeny, Prevalence, Epidemiology, China, Asia, Human, ENT disease, Pharynx disease, Malignant tumor
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 98-0210162
Code Inist : 002B10B01. Création : 11/09/1998.