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Biomedical subjects

Georg Klein

Publications and source records attributed to Georg Klein.

4 recordsLinked to original sources
PubMed2003

The uterine cervix--a new member of the family of immunologically exceptional sites?

As a bystander effect, immune responses against infectious organisms can damage normal cells. Immune privilege can protect such endangered tissues from immune destruction. One example is the eye where potentially devastating inflammatory reactions are prevented by active, counter-regulating processes that prevent lymphocyte activation. Recent epidemiological data from transplant patients in Sweden showed, surprisingly, that the frequency of cervical cancers did not increase in organ transplant recipients, in contrast to cancers of the vagina, vulva and anus. The same subtypes of HPV are known to be involved in the genesis of all these tumors. The immune surveillance mechanisms known to antagonize the outgrowth of virally-associated neoplasms would have been expected to affect them all. The special case of cervical carcinomas may reflect a site-specific immune privilege that could have evolved to protect the integrity of the reproductive function.

Cell Transformation, Viral↗
PubMed2002

The Epstein-Barr virus ZEBRA protein activates transcription from the early lytic F promoter by binding to a promoter-proximal AP-1-like site.

The ZEBRA protein encoded by the Epstein-Barr virus (EBV) genome activates a switch from the latent to the lytic gene expression programme of the virus. ZEBRA, a member of the basic leucine zipper family of DNA-binding proteins, is a transcriptional activator capable of inducing expression from several virus lytic cycle promoters by binding to activator protein 1 (AP-1)-like sites. The Epstein-Barr virus BamHI F promoter, Fp, was for some time believed to initiate EBNA1-specific transcription in EBV-transformed latent cells. More recent data, however, show that Fp is an early lytic promoter and that the dominant EBNA1 gene promoter in latent cells is Qp, located about 200 bp downstream of Fp. In the present investigation we confirm that Fp displays the characteristics of a lytic promoter. Fp is downregulated in latently EBV-infected cells, both in the endogenous virus genome and in reporter plasmids that carry Fp regulatory sequences upstream of position -136 and down to +10 relative to the Fp transcription start site (+1), and is activated on induction of the virus lytic cycle. We show that the repression of Fp in latent stages of infection can be abolished by ZEBRA, and demonstrate that ZEBRA activates Fp through a direct interaction with an AP-1-like site at position -52/-46 in the promoter-proximal Fp region.

B-Lymphocytes↗