Biomedical subjects

C Aepinus

Publications and source records attributed to C Aepinus.

22 records · Page 2Linked to original sources

PubMed1991

Mutational analysis of functional domains in the HIV-1 Rev trans-regulatory protein.

HIV-1 replication depends on the expression of trans-regulatory genes (tat, rev) encoded in the 3' part of the retroviral genome. HIV-1 Rev trans-activator protein allows the cytoplasmic translocation of incompletely spliced retroviral mRNA which is required for the translational switch from regulatory (Tat, Rev, Nef) to structural proteins (Gag, Pol, Env). The HIV-1 Rev regulatory protein comprises an activation domain (RAD) and a RNA binding domain (RBD). Both functional domains are not well defined and the RBD appears to overlap with the nuclear localization signal (NLS). Our mutational analysis localized the Rev protein domain important for RRE (nucleotide 7781 to 8000) binding in vitro to amino acid residues 31 to 50. Mutations in this domain always resulted in exclusion from the nucleoli. Furthermore, these mutants did not support Rev-dependent p24 Gag production in vivo. Sequences immediately upstream of this domain (RevM4, RevM19) were attenuated in their in vivo activity possibly indicating a role in Rev protein oligomerization. The observed tight correlation between subcellular localization and RNA binding in vitro indicates that this short stretch of amino acids supports two essential functions required for HIV-1 replication.

Amino Acid Sequence↗

PubMed1991

In vitro binding of human T-cell leukemia virus rex proteins to the rex-response element of viral transcripts.

Human T-cell leukemia virus (HTLV-I, HTLV-II) rex protein function is required for the cytoplasmic expression of incompletely spliced viral transcripts encoding structural proteins. The effect is mediated by a cis-acting rex-response element (RRX) which is located near the 3' end of all viral mRNAs. We show that rex polypeptides of HTLV-I and HTLV-II expressed in Escherichia coli are capable of specifically binding RRX-containing transcripts of both viruses in cell-free assays. Binding analyses with deletion variants of rex proteins revealed a domain with RNA-binding activity in the first 77 N-terminal amino acids. Removal of a basic peptide of 19 amino acids from the N terminus abrogated RNA binding, whereas a beta-galactosidase fusion protein containing this peptide bound to the RRX. These results suggest that direct binding of rex protein to the RRX is important for rex-mediated regulation of viral gene expression and that a short stretch of positively charged amino acids contributes to the specific binding of rex to its target RNA.

Carrier Proteins↗

PubMed1990

A rev/beta-galactosidase fusion protein binds in vitro transcripts spanning the rev-responsive element of human immunodeficiency virus type 1 (HIV-1).

The rev protein of human immunodeficiency virus type 1 (HIV-1), a phosphoprotein of 20 kDa apparent molecular mass, is essential to target the mRNA for virion polypeptides into the cytoplasm. This effect is mediated by a specific RNA stretch (rev-responsive element = RRE) localized within a 3'-terminal segment of the mRNA encoding virion proteins. We present evidence that rev expressed as a beta-galactosidase fusion protein in E. coli forms a complex with in vitro transcripts containing the RRE; it can be precipitated by monoclonal antibodies with rev or beta-galactosidase specificity. In addition, specific binding of rev protein to RNA could be demonstrated by Northwestern blotting.

Animals↗

PubMed1990

Monoclonal antibodies directed against the rev protein of human immunodeficiency virus type 1.

The rev (art/trs) protein of human immunodeficiency virus type 1 (HIV-1), a phosphoprotein of 20 K apparent molecular weight, is essential to target the mRNA for virion polypeptides into the cytoplasm. The rev protein was expressed in Escherichia coli as a beta-galactosidase fusion protein with a cleavage site for proteinase factor Xa. The rev-specific fragment was isolated to immunize mice. Five stable hybridoma cell lines were obtained producing monoclonal antibodies that reacted with rev protein in Western blot and ELISA. Using the monoclonal antibodies in indirect immunofluorescence, the rev protein could be localized in the nucleus, mostly in the nucleoli, of Hela cells that were transfected with a eukaryotic rev expression plasmid.

Animals↗