The Fission Yeast XMAP215 Homolog Dis1p Is Involved in Microtubule Bundle Organization

Microtubules are essential for a variety of fundamental cellular processes such as organelle positioning and control of cell shape. Schizosaccharomyces pombe is an ideal organism for studying the function and organization of microtubules into bundles in interphase cells. Using light microscopy and electron tomography we analyzed the bundle organization of interphase microtubules in S. pombe. We show that cells lacking ase1p and klp2p still contain microtubule bundles. In addition, we show that ase1p is the major determinant of inter-microtubule spacing in interphase bundles since ase1 deleted cells have an inter-microtubule spacing that differs from that observed in wild-type cells. We then identified dis1p, a XMAP215 homologue, as factor that promotes the stabilization of microtubule bundles. In wild-type cells dis1p partially co-localized with ase1p at regions of microtubule overlap. In cells deleted for ase1 and klp2, dis1p accumulated at the overlap regions of interphase microtubule bundles. In cells lacking all three proteins, both microtubule bundling and inter-microtubule spacing were further reduced, suggesting that Dis1p contributes to interphase microtubule bundling

The interest of the Spanish network of investigators in back pain for rehabilitation physician

Background: The Spanish Back Pain Research Network (REIDE) brings together teams of researchers and clinicians who are interested in nonspecific neck and back pain (BP). Its objective is to improve the efficacy, safety, effectiveness, and efficiency of the clinical management of BP. Method: The Network welcomes clinicians and researchers interested in BP. The only requirement to become a member of REIDE is to take part in one of its research projects, and any member can propose a new one. The Network supports those projects that are of interest to two or more groups by assuming their administration and management, which allows the researchers to focus on their task. Its working method ensures methodological quality, a multidisciplinary approach, and the clinical relevance of those projects that are carried out. Results: 179 researchers from 11 areas in Spain are involved in REIDE, including experts in all of the relevant fields of BP research. Most Spanish studies on BP that have been published in international scientific journals come from the teams involved in REIDE, and it currently has 13 ongoing research projects. Conclusions: The Network can help to enhance research among rehabilitation specialists who are interested in BP, and can contribute to the development of research projects which are of interest to the specialty. © 2005 Sociedad Española de Rehabilitación y Medicina Física (SERMEF) y Elsevier España, S.L

Parthenogenesis in insects: the centriole renaissance

Building a new organism usually requires the contribution of two differently shaped haploid cells, the male and female gametes, each providing its genetic material to restore diploidy of the new born zygote. The successful execution of this process requires defined sequential steps that must be completed in space and time. Otherwise, development fails. Relevant among the earlier steps are pronuclear migration and formation of the first mitotic spindle that promote the mixing of parental chromosomes and the formation of the zygotic nucleus. A complex microtubule network ensures the proper execution of these processes. Instrumental to microtubule organization and bipolar spindle assembly is a distinct non-membranous organelle, the centrosome. Centrosome inheritance during fertilization is biparental, since both gametes provide essential components to build a functional centrosome. This model does not explain, however, centrosome formation during parthenogenetic development, a special mode of sexual reproduction in which the unfertilized egg develops without the contribution of the male gamete. Moreover, whereas fertilization is a relevant example in which the cells actively check the presence of only one centrosome, to avoid multipolar spindle formation, the development of parthenogenetic eggs is ensured, at least in insects, by the de novo assembly of multiple centrosomes. Here, we will focus our attention on the assembly of functional centrosomes following fertilization and during parthenogenetic development in insects. Parthenogenetic development in which unfertilized eggs are naturally depleted of centrosomes would provide a useful experimental system to investigate centriole assembly and duplication together with centrosome formation and maturation