Zhao Y, Yu M, Chen M, Yogev R; Conference on Retroviruses and Opportunistic Infections.

Program Abstr 4th Conf Retrovir Oppor Infect Conf Retrovir Oppor Infect 4th 1997 Wash DC. 1997 Jan 22-26; 4th: 77 (abstract no. 68).

Children's Memorial Hospital, Chicago, IL.

We have reported that HIV-1 Vpr induces various changes in cell morphology in fission yeast. These morphogenetic changes were evaluated by the formation and organization of the cytoskeletal apparatus such as actin localization and cell wall chitin deposition. We used conventional fluorescence microscopy to observe actin distribution (by TRITC-labelled phalloidin staining) and cell wall deposition (by chitin-specific Calcofluor staining) in cells in which vpr was expressed or repressed. Normally growing cells under vpr-repressed conditions can be clearly identified by uniform Calcofluor staining on the cell wall or by phalloidin staining as actin patches. However, highly localized and intensified Calcofluor staining was found accumulating on the cell wall in Vpr-induced cells and these changes were parallelled the formation of irregular protruding structures, suggesting that change of cell wall structure is at least partially responsible for the specific morphological alterations in these cells. Actin was also found dispersed in these cells rather than localized as patches, indicating possible disruption of the anchorage of actin to the cell membrane and disruption of cytoskeletal structure. Therefore, loss of actin localization may also contribute to Vpr-induced morphological changes. These profound structural alterations induced by Vpr suggested a potential detrimental effect to the cells. Indeed, almost all of the cells failed to grow on vpr-inducing agar plates after 24-48 hours vpr-induction in liquid culture. Cell viability assessed by measuring intracellular esterase activity and cell membrane permeability after 48 hours vpr-induction in culture further confirmed that these cells were no longer viable. Intriguingly, Vpr-induced cells showed aberrant nuclear morphology mimicking fragmented chromatin, implying possible apoptosis. Tests are in progress to assess this possibility.

Publication Types:

• Meeting Abstracts

Keywords:

• Actins
• Apoptosis
• Cell Wall
• Cytoskeleton
• Genes, vpr
• HIV-1
• Schizosaccharomyces
• Schizosaccharomyces pombe Proteins
• genetics

Other ID:

• 97926087

UI: 102223096

From Meeting Abstracts