Acessibilidade / Reportar erro

Modulation of GFAP gene promoter by neurons during development

MODULATION OF GFAP GENE PROMOTER BY NEURONS DURING DEVELOPMENT**Supported by PRONEX/MCT, FAPERJ, CNPq, CAPES. E-mail: fgomes@anato.ufrj.br

FLÁVIA CARVALHO ALCANTARA GOMES1, TÂNIA CRISTINA L. DE SAMPAIO E SPOHR1, ELEN DA SILVA1, DENISE PAULIN2AND VIVALDO MOURA NETO1

1

2Université Paris VII, Paris, France.

Neuron-glial interactions play pivotal role in several steps of CNS morphogenesis, since the early stages of neurogenesis until the later events of neural connections establishment. Most of our knowledge concerning such interactions lies on data obtained from glial cells effects on neuronal morphogenesis. However, several evidences have been accumulated in the past years pointing to a mutual influence between these two cells. While there is compelling evidence of neuronal factors on oligodendrocytes and Schwann cells, there is still lack of data of their effects on astrocytes. In order to access this question we have established an astrocyte-neuron coculture system by using a transgenic mice bearing part of the astrocyte maturation marker glial fibrillary acidic protein (GFAP) gene promoter linked to the b-galactosidase (b-gal) reporter gene. New insights into the biological function of GFAP have been provided by the generation of GFAP transgenic and null mice. Increasing evidences have accumulated pointing to a role of GFAP in neuron-glia interactions such as modulation of astrocyte stellation, axon sprouting and regeneration. We have recently demonstrated that cortical neurons can induce GFAP gene promoter followed by transgenic astrocyte differentiation, by secreting brain region-specific soluble factors (Gomes F et al. 1999 Glia 26: 97). Further, neuronal mediated astrocyte differentiation is dependent on neurons and astrocyte developmental stage. Younger neurons derived from 14-16 embryonic days (E14-16) wild type mice are more efficient in promoting astrocyte differentiation than those derived from E18 mice. Similarly, astrocytes also exhibit a timed schedule developed responsiveness to neuronal influences with embryonic astrocytes showing to be more responsive to neuronal influence than newborn and late postnatal astrocytes. Together these data support the concept that within the context of brain development, neuron-glia interactions are not unique, rather they present a great complexity and heterogeneity throughout CNS. Although neuronal effects mechanisms on astrocytes are still far from being well understood, we have demonstrated that neurons are able to activate GFAP gene promoter and astrocytic differentiation program guided by a development clock. Those data might provide new insights on astrocytes precursors differentiation and implicate neuron-glial interactions in gliogenesis as well as in the developmental plasticity of the brain. — ( June 27, 2000 ).

  • *
    Supported by PRONEX/MCT, FAPERJ, CNPq, CAPES.
    E-mail:
  • Publication Dates

    • Publication in this collection
      05 Oct 2000
    • Date of issue
      Sept 2000
    Academia Brasileira de Ciências Rua Anfilófio de Carvalho, 29, 3º andar, 20030-060 Rio de Janeiro RJ Brasil, Tel: +55 21 3907-8100 - Rio de Janeiro - RJ - Brazil
    E-mail: aabc@abc.org.br