Knuchel M, Lal RB; Conference on Retroviruses and Opportunistic Infections.
Program Abstr 3rd Conf Retrovir Oppor Infect Conf Retrovir Oppor Infect 3rd 1996 Wash D C. 1996 Jan 28-Feb 1; 3rd: 141.
LIF is a growth factor with pleiotropic activity that shares functional redundancy with interleukin 6 (IL-6). Since HIV-1 infection can upregulate the expression of both, LIF and IL-6, we sought to determine the effects of HIV infection on LIF expression. In vitro culture of PBMC from HIV-infected patients demonstrated a production of LIF which paralleled the p24 antigen production. To investigate the molecular mechanisms controlling LIF gene expression, we cloned the human LIF promoter into a chloramphenicol acetyl transferase (CAT) reporter gene vector. Using transient transections of T cell lines and CAT assays, we have identified the cis-response elements on the promoter: a positive element, API (-362/-352) and two negative regulatory elements at -542/-532 and -208/-93. In order to define the role of the HIV transactivator tat in inducing LIF transcription, cotransfection of the LIF-CAT construct with a tat-expressing plasmid were performed resulting in a three fold induction of LIF. However, deletion of the negative regulatory site at -542bp, as well as point mutation of this site resulted in a 50% loss of induction. Thus, the transactivating tat-response element seem to overlap with this negative regulatory site. Interestingly, this site, CAGTTCCACTT, differs only by one base from the IFNb silencer (CAGTTTCACTTCT). The importance of derepression of "silent" cytokines in T cell lymphocytes will be discussed.
Publication Types:
Keywords:
- Acquired Immunodeficiency Syndrome
- Animals
- Cats
- Cell Line
- Chloramphenicol O-Acetyltransferase
- Gene Products, tat
- Genes, tat
- Growth Inhibitors
- HIV
- HIV Core Protein p24
- HIV Infections
- HIV Long Terminal Repeat
- HIV-1
- Humans
- In Vitro
- Interleukin-6
- Promoter Regions (Genetics)
- Protein Binding
- Trans-Activators
- Transcription, Genetic
- genetics
- immunology
Other ID:
UI: 102216527
From Meeting Abstracts