Authors:E. Méhes, Dominique Mornet and Veronika Jancsik
The dystrophin glycoprotein complex (DGC) is a membrane-associated protein complex binding extracellular matrix (ECM) molecules, such as laminin and forming a bridge towards the cytoskeleton. The molecular composition of the DGC is cell type dependent and it is involved in cell adhesion and motility. Here we present immunocytochemical localization of beta-dystroglycan, the central member of the DGC, utrophin and Dp71f, the spliced 71 kDa dystrophin protein product of the DMD gene, in cultured retinal Muller glial cells. It is shown that beta-dystroglycan and utrophin are colocalized in clusters in all parts of Muller cells including the lamellipodium and leading edge of migrating cells. As a contrast, Dp71f labels are distinct from beta-dystroglycan and confined to the perinuclear cytoplasm of Muller cells indicating that Dp71f is not a member of the DGC in cultured Muller cells.
Authors:Balázs Gerics, Ferenc Szalay, Péter Sótonyi and Veronika Jancsik
Melanin-concentrating hormone (MCH), the neuropeptide produced mainly in the hypothalamus, plays an operative role in regulating food intake and the sleep/wake cycle. Considering that these physiological functions pursue diurnal variations, we checked whether the total hypothalamic MCH level depends on the time of the day. The aggregated MCH peptide content of the whole MCH neuron population was significantly higher at the end of the sleeping period (lights on), than at the end of the active period (lights off). This result, together with earlier observations, indicates that in contrast to the MCH gene expression, the level of MCH peptide is object of circadian variation in the hypothalamus.
Authors:Diana Hazai, Katalin Halasy, D. Mornet, F. Hajós and Veronika Jancsik
It has previously been demonstrated that Dp71, the most abundant dystrophin protein in the brain, is mainly localized in the postsynaptic densities. Here we show the localization of Dp71f, one of the splice variants of this protein, within the CA3 region of the hippocampus. Immunopositivity occurs in the postsynaptic density of small asymmetrical axospinous and axodendritic synapses, while it is absent in the postsynaptic densities of the axospinous synapses of the large mossy fiber terminals. Dp71f immunoreactivity was found to be attached to the membranes of the mossy fibers in the stratum lucidum of the CA3 area. In a certain population of thin myelinated axons the protein seems to be present within the axon proper. These data support the notion of a physiological role of Dp71f distinct from other dystrophin isoforms present in the central nervous system.