Stable association of mitotic cyclin B/Cdc2 to replication origins prevents endoreduplication.

We show that in fission yeast the mitotic B type cyclin Cdc13/Cdc2 kinase associates with replication origins in vivo. This association is dependent on the origin recognition complex (ORC), is established as chromosomes are replicated, and is maintained during G2 and early mitosis. Cells expressing an orp2 (ORC2) allele that reduces binding of Cdc13 to replication origins are acutely prone to chromosomal reduplication.

Reassessment of the effects of cycloheximide on mossy fiber sprouting and epileptogenesis in the pilocarpine model of temporal lobe epilepsy.

A feature of animal models of temporal lobe epilepsy and the human disorder is hippocampal sclerosis and Timm stain in the inner molecular layer (IML) of the dentate gyrus, which represents synaptic reorganization and may be important in epileptogenesis. We reassessed the hypothesis that pre-treatment with cycloheximide (CHX) prevents Timm staining in the IML following pilocarpine (PILO)-induced status epilepticus (a multifocal model of temporal lobe epilepsy), but allows epileptogenesis (i.e.

Excitatory synaptic input to granule cells increases with time after kainate treatment.

Temporal lobe epilepsy is usually associated with a latent period and an increased seizure frequency following a precipitating insult. After kainate treatment, the mossy fibers of the dentate gyrus are hypothesized to form recurrent excitatory circuits between granule cells, thus leading to a progressive increase in the excitatory input to granule cells. Three groups of animals were studied as a function of time after kainate treatment: 1-2 wk, 2-4 wk, and 10-51 wk.

Whole-cell recordings from preoptic/hypothalamic slices reveal burst firing in gonadotropin-releasing hormone neurons identified with green fluorescent protein in transgenic mice.

Central control of reproduction is governed by a neuronal pulse generator that underlies the activity of hypothalamic neuroendocrine cells that secrete GnRH. Bursts and prolonged episodes of repetitive action potentials have been associated with hormone secretion in this and other neuroendocrine systems. To begin to investigate the cellular mechanisms responsible for the GnRH pulse generator, we used transgenic mice in which green fluorescent protein was genetically targeted to GnRH neurons.

Genetic targeting of green fluorescent protein to gonadotropin-releasing hormone neurons: characterization of whole-cell electrophysiological properties and morphology.

GnRH neurons form the final common pathway for central control of reproduction, with regulation achieved by changing the pattern of GnRH pulses. To help elucidate the neurobiological mechanisms underlying pulsatile GnRH release, we generated transgenic mice in which the green fluorescent protein (GFP) reporter was genetically targeted to GnRH neurons. The expression of GFP allowed identification of 84-94% of immunofluorescently-detected GnRH neurons.