The ubiquitin ligase COP1 regulates cell cycle and apoptosis by affecting p53 function in human breast cancer cell lines.

Background: The E3 ubiquitin ligase constitutive photomorphogenic 1 (COP1) mediates cell survival, growth, and development, and interacts with the tumor suppressor protein p53 to induce its ubiquitination and degradation. Recent studies reported that COP1 overexpression is associated with increased cell proliferation, transformation, and disease progression in a variety of cancer types. In this study, we investigated whether COP1 regulates p53-mediated cell cycle arrest and apoptosis in human breast cancer cell lines.

Identification of the HIV-1 packaging RNA sequence (Ψ) as a major determinant for the translation inhibition conferred by the HIV-1 5' UTR.

The HIV-1 5' untranslated region (UTR) contains conserved sequences and unique structural motifs associated with many steps in virus replication. Because unspliced HIV mRNA containing the full-length UTR serves as a template for replication and transcription as well as packaging genomic RNA into virion, it has been postulated that the UTR may play a role in translational regulation. However, the effect and the region(s) responsible for translation control remain controversial.