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V Moura Neto

Publications and source records attributed to V Moura Neto.

39 records · Page 3Linked to original sources

Astrocytic cerebellar cell clones synthesize the beta' isoforms of the beta-tubulin protein family.

We have analysed the isotubulin pattern of three astrocytic cell clones, derived from spontaneously established permanent cell cultures originating from 8-day postnatal mice cerebellar explants, in comparison with that of primary astroglial cultures from embryonic brain and cerebellum. These astrocytic clones, which may represent the different astroglial cell types of mouse cerebellum, did not produce the alpha- and beta-acidic isoforms, these being found only in cells of neuronal lineage. However, the three astrocytic clones, but not the primary astroglial cultures, did synthesize the beta'-tubulin isoforms; in addition quantitative analysis of the beta' proteins showed a positive correlation between the ability of the cells to extend processes and their synthesis of the beta' isoforms. These data suggest that the presence of beta'-tubulin is not specific for neuronal cells but may be related to the ability of cells from the nervous system to extend processes.

Animals↗

Presence of actin in oncornaviruses.

A 43K protein present in avian myeloblastosis virus has been identified as actin by 2D gel electrophoresis and peptide mapping proteolysis. Electron microscopy of chicken embryo fibroblasts infected with different pseudotypes of oncornaviruses treated with anti-actin antibody showed positive staining at the level of the virions especially on buds. Our results indicate that this actin is unlikely to have been artefactually absorbed at the virion surface during its preparation. It may therefore play a possible role in the budding of enveloped virions.

Actins↗

Microheterogeneity of tubulin proteins in neuronal and glial cells from the mouse brain in culture.

The microheterogeneity of the alpha and beta isoforms of tubulin in brain cells in culture was studied. The cells were prepared from two precise regions of the embryonic mouse brain (ED15), the striatum and the mesencephalon. It was possible to maintain virtually pure cultures of neuronal or glial cells up to 1 and 4 weeks in vitro, respectively. The tubulin heterogeneity of striatal and mesencephalic neurons was found to be very similar after a few days in culture. More precise examination of pure neurons from the striatum revealed that their tubulin content after 7 days in vitro exhibited the same degree of complexity as a control extract from a 4 day-old mouse brain. In fact, we could detect the presence of at least six alpha and nine beta tubulin isoforms. Among these isoforms a specific family of beta proteins (beta' tubulin) and the more acidic alpha proteins were present. Since these isoforms have, up to now, been found only in tubulin extracts prepared from the nervous system, our experiments suggest that they belong to the neuronal subpopulation of this tissue. This point is reinforced by their complete absence from the tubulin proteins extracted from pure glial cells even after several weeks in vitro. These results lead us to propose that brain tubulin microheterogeneity is associated with the presence of neurons and not of glia and may, therefore, play a specific role in maintaining neuronal shape and function.

Animals↗