Abstract: The present invention embraces an RNA replicon (self-amplifying RNA vector (saRNA)) that can be replicated by a replicase of a self-replicating virus, e.g., a replicase of alphavirus origin. According to the invention, translation of the replicase open reading frame is uncoupled from a 5?-terminal cap by placing translation of the replicase open reading frame under the translational control of an internal ribosome entry site (IRES). Thereby the initiation of translation depends on the molecular properties of the respective IRES, which compared to cap-dependent translation may require less or no cellular initiation factors to direct the ribosome to the translational start site. According to the invention, IRES-controlled replicase translation may allow the use of uncapped synthetic saRNA. Furthermore, the use of an IRES provides for the option to insert additional transgenes upstream to the IRES.

Abstract: The present invention embraces a RNA replicon that can be replicated by a replicase of alphavirus origin. The RNA replicon comprises sequence elements required for replication by the replicase, but these sequence elements do not encode any protein or fragment thereof, such as an alphavirus non-structural protein or fragment thereof. Thus, in the RNA replicon according to the invention, sequence elements required for replication by the replicase and protein-coding region(s) are uncoupled. According to the present invention the uncoupling is achieved by the removal of at least one initiation codon compared to a native alphavirus genomic RNA. In particular, the RNA replicon comprises a 5? replication recognition sequence, wherein the 5? replication recognition sequence is characterized in that it comprises the removal of at least one initiation codon compared to a native alphavirus 5? replication recognition sequence.

Abstract: The present invention embraces a RNA replicon that can be replicated by a replicase of alphavirus origin. The RNA replicon comprises sequence elements required for replication by the replicase, but these sequence elements do not encode any protein or fragment thereof, such as an alphavirus non-structural protein or fragment thereof. Thus, in the RNA replicon according to the invention, sequence elements required for replication by the replicase and protein-coding region(s) are uncoupled. According to the present invention the uncoupling is achieved by the removal of at least one initiation codon compared to a native alphavirus genomic RNA. In particular, the RNA replicon comprises a 5? replication recognition sequence, wherein the 5? replication recognition sequence is characterized in that it comprises the removal of at least one initiation codon compared to a native alphavirus 5? replication recognition sequence.

Abstract: The present invention describes a virus-derived factor which when provided to cells, e.g., by transfecting the cells with RNA encoding the virus-derived factor, enhances expression of RNA encoding a peptide or protein in the cells. In particular, the virus-derived factor enhances survival of cells, in particular when transfected repetitively with RNA, and reduces an IFN response of cells to transfected RNA. Accordingly, the present invention provides methods and means for enhancing expression of RNA in cells. The cells are preferably transfected with the RNA.

Abstract: The present invention generally relates to systems and methods suitable for high-level protein production. While one or more elements of the present invention are derived from an alphavirus, the present invention does not require propagation of virus particles. In particular, a system comprising two separate RNA molecules is foreseen, each comprising a nucleotide sequence derived from an alphavirus: one RNA molecule comprises a RNA construct for expressing alphavirus replicase, and one RNA molecule comprises a RNA re pi icon that can be replicated by the replicase in trans. The RNA construct for expressing alphavirus replicase comprises a 5?-cap. It was surprisingly found that the 5?-cap is suitable for efficiently driving expression of a transgene from the replicon in trans. The system of the present invention enables expression of a protein of interest in a cell or organism, but is not associated with undesired virus-particle formation.

Abstract: The present invention embraces a RNA replicon that can be replicated by a replicase of alphavirus origin. The RNA replicon comprises sequence elements required for replication by the replicase, but these sequence elements do not encode any protein or fragment thereof, such as an alphavirus non-structural protein or fragment thereof. Thus, in the RNA replicon according to the invention, sequence elements required for replication by the replicase and protein-coding region(s) are uncoupled. According to the present invention the uncoupling is achieved by the removal of at least one initiation codon compared to a native alphavirus genomic RNA. In particular, the RNA replicon comprises a 5? replication recognition sequence, wherein the 5? replication recognition sequence is characterized in that it comprises the removal of at least one initiation codon compared to a native alphavirus 5? replication recognition sequence.

Abstract: The present invention embraces a RNA replicon that can be replicated by a replicase of alphavirus origin and comprises an open reading frame encoding a chain of a T cell receptor or of an artificial T cell receptor. Such RNA replicons are useful for expressing a T cell receptor or an artificial T cell receptor in a cell, in particular an immune effector cell such as a T cell. Cells engineered to express such T cell receptor or artificial T cell receptor are useful in the treatment of diseases characterized by expression of antigens bound by the T cell receptor or artificial T cell receptor.

Abstract: The present invention embraces a RNA replicon that can be replicated by a replicase of alphavirus origin and comprises an open reading frame encoding a reprogramming factor. Such RNA replicons are useful for expressing a reprogramming factor in a cell, in particular a somatic cell. Cells engineered to express such reprogramming factors are useful in cell transplantation therapies.

Abstract: The invention relates to APOBEC4 proteins and N- or C-terminally modified APOBEC4 proteins for the modulation of the release of retroviruses or viral particles thereof from cells and various uses thereof. Expression of APOBEC4 or N-terminally stabilized APOBEC4 protein in a cell leads to an increased viral production, while expression of C-terminally modified APOBEC4 protein leads to a decrease in viral production.