INVESTIGADORES
SANTANDER Veronica Silvina
artículos
Título:
Lack of stabilized microtubules as a result of the absence of major maps in CAD cells does not preclude neurite formation
Autor/es:
BISIG, GASTON; CHESTA, MARIA; ZAMPAR, GUILLERMO; PURRO, SILVIA; SANTANDER, VERÓNICA; ARCE, CARLOS
Revista:
FEBS Journal
Editorial:
Blackwell Publishing Ltd Company
Referencias:
Lugar: Inglaterra; Año: 2009 vol. 276 p. 7110 - 7123
ISSN:
0014-2956
Resumen:
In many laboratories, the requirement of microtubule-associated proteins
(MAPs) and the stabilization of microtubules for the elongation of neurites
has been intensively investigated, with controversial results being obtained.
We have observed that the neurite microtubules of Cath.a-differentiated
(CAD) cells, a mouse brain derived cell, are highly dynamic structures, and
so we analyzed several aspects of the cytoskeleton to investigate the molecular
causes of this phenomenon. Microtubules and microfilaments were present
in proportions similar to those found in brain tissue and were
distributed similarly to those in normal neurons in culture. Neurofilaments
were also present. Analysis of tubulin isospecies originating from post-translational
modifications revealed an increased amount of tyrosinated tubulin,
a diminished amount of the detyrosinated form and a lack of the Delta2
form. This tyrosination pattern is in agreement with highly dynamic microtubules.
Using western blot analyses with specific antibodies, we found that
CAD cells do not express several MAPs such as MAP1b, MAP2, Tau, doublecortin,
and stable-tubule-only-peptide. The presence of the genes corresponding
to these MAPs was verified. The absence of the corresponding
mRNAs confirmed the lack of expression of these proteins. The exception
was Tau, whose mRNA was present. Among the several MAPs investigated,
LIS1 was the only one to be expressed in CAD cells. In addition, we
determined that neurites of CAD cells form and elongate at the same rate
as processes in a primary culture of hippocampal neurons. Treatment with
nocodazol precluded the formation of neurites, and induced the retraction
of previously formed neurites. We conclude that the formation and elongation
of neurites, at least in CAD cells, are dependent on microtubule
integrity but not on their stabilization or the presence of MAPs.