[HTLV-I and leukemogenesis].
Human T-cell leukemia virus type I (HTLV-I) is a causative virus of adult T-cell leukemia (ATL). ATL is a highly aggressive neoplastic disease of CD4 positive T lymphocyte, which is featured by the pleomorphic tumor cells with hypersegmented nuclei, called " flower cell". HTLV-I increases its copy number by clonal proliferation of the host cells, not by replication of the virus. Therefore, HTLV-I eventually induces ATL. Tax, encoded by HTLV-I pX region, has been recognized as a protein that plays a central role of the transformation of HTLV-I-infected cells by its pleiotropic actions. However, fresh ATL cells frequently lose Tax protein expression by several mechanisms. Recently, HBZ was identified in the complementary strand of HTLV-I and it is suggested that HBZ is a critical gene in leukemogenesis. Furthermore, there is a long latency period before onset of ATL, indicating the multistep mechanisms of leukemogenesis. Therefore, it is suggested that multiple factors, such as viral proteins, genetic and epigenetic changes of host genome, and immune status of the hosts, could be implicated in leukemogenesis of ATL.
Yasunaga
Jun-ichirou
J
Laboratory of Human Tumor Viruses Department of Viral Oncology Institute for Virus Research, Kyoto University. jyasunag@virus1.virus.kyoto-u.ac.jp
Matsuoka
Masao
M
D050976:Basic-Leucine Zipper Transcription Factors / Q000502:physiology; D015496:CD4-Positive T-Lymphocytes; D002472:Cell Transformation, Viral; D016356:Gene Products, tax / Q000502:physiology; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000473:pathology / Q000821:virology*; D012191:Retroviridae Proteins; D014764:Viral Proteins / Q000502:physiology; D017735:Virus Latency
D050976:Basic-Leucine Zipper Transcription Factors; D016356:Gene Products, tax; C479751:HBZ protein, human T-cell leukemia virus type I; D012191:Retroviridae Proteins; D014764:Viral Proteins