The signal peptide of mouse mammary tumor virus-env: a phosphoprotein tumor modulator.

Signaling and Regulation The Signal Peptide of Mouse Mammary Tumor Virus-Env: A Phosphoprotein Tumor Modulator

Mousemammary tumor virus (MMTV) is associated primarily withmammary carcinomas and lymphomas. The signal peptide of theMMTV envelope precursor is uniquely targeted to nucleoli of cells that harbor the virus, where it can function as a nuclear export factor for intron-containing transcripts. Antibodies to this signal peptide, which we refer to as p14,were previously shown to label nucleoli in a ...

Nucleotide sequencing of an apparent proviral copy of env mRNA defines determinants of expression of the mouse mammary tumor virus env gene.

To extend our understanding of the organization and expression of the mouse mammary tumor virus genome, we determined the nucleotide sequence of large regions of a cloned mouse mammary tumor virus strain C3H provirus that appears to be a DNA copy of env mRNA. In conjunction with analysis of several additional clones of integrated and unintegrated mouse mammary tumor virus DNAs, we came to the f...

Retroviral Rem protein requires processing by signal peptidase and retrotranslocation for nuclear function.

Mouse mammary tumor virus (MMTV) is a complex murine retrovirus that encodes an HIV Rev-like export protein, Rem, from a doubly spliced version of envelope (Env) mRNA. Previously, the N-terminal 98-amino acid sequence of Rem, which is identical to Env signal peptide (SP), and full-length Rem were shown to be functional in a reporter assay that measures a postexport function. Here we show that M...

Altered mouse mammary tumor virus transcript synthesis in T-cell lymphoma cells.

Proviral copies of mouse mammary tumor virus (MMTV) are known to be amplified in certain T-cell lymphomas. Transcription of the amplified MMTV proviruses was studied in detail in two T-cell lymphoma lines and showed the production of deletions and premature termination of env mRNAs and the premature termination of gag transcripts. EL-4 cells produce three env mRNAs, and sequence analysis of cDN...

Tumor Virus Superantigen Transcriptional Activation of Mammary Chromatin Structural Change in the Role of Ikaros, Demethylation, and Transcripts in Lymphomas of SJL/J Mice: Mammary Tumor Virus Superantigen Transcriptional Activator Initiated env Regulation of Mouse Mammary Tumor Virus