continued stabilization of the nuclear higher-order structure of post-mitotic neurons in vivo持续稳定的核高阶结构post-mitotic神经元体内.pdf

Continued Stabilization of the Nuclear Higher-Order Structure of Post-Mitotic Neurons In Vivo ¤ Janeth Alva-Medina, Apolinar Maya-Mendoza , Myrna A. R. Dent, Armando Aranda-Anzaldo* ´ ´ ´ ´ ´ Laboratorio de Biologıa Molecular y Neurociencias, Facultad de Medicina, Universidad Autonoma del Estado de Mexico, Toluca, Estado de Mexico, Mexico Abstract Background: Cellular terminal differentiation (TD) correlates with a permanent exit from the cell cycle and so TD cells become stably post-mitotic. However, TD cells express the molecular machinery necessary for cell proliferation that can be reactivated by experimental manipulation, yet it has not been reported the stable proliferation of any type of reactivated TD cells. Neurons become post-mitotic after leaving the ventricular zone. When neurons are forced to reenter the cell cycle they invariably undergo cell death. Wider evidence indicates that the post-mitotic state cannot solely depend on gene products acting in trans, otherwise mutations in the corresponding genes may lead to reentry and completion of the cell cycle in TD cells, but this has not been observed. In the interphase, nuclear DNA of metazoan cells is organized in supercoiled loops anchored to a nuclear nuclear matrix (NM). The DNA-NM interactions define a higher-order structure in the cell nucleus (NHOS). We have previously compared the NHOS of aged rat hepatocytes with that of early post-mitotic rat neurons and our results indicated that a very stable NHOS is a common feature of both senescent and post-mitotic cells in vivo. Principal Findings: In the present work we compared the NHOS in rat neurons from different post-natal ages. Our results