The olfactory critical period is determined by activity-dependent Sema7A/PlxnC1 signaling within glomeruli.

In mice, early exposure to environmental odors affects social behaviors later in life. A signaling molecule, Semaphorin 7A (Sema7A), is induced in the odor-responding olfactory sensory neurons. Plexin C1 (PlxnC1), a receptor for Sema7A, is expressed in mitral/tufted cells, whose dendrite-localization is restricted to the first week after birth.

Author Correction: Sema7A/PlxnCl signaling triggers activity-dependent olfactory synapse formation.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Primary dendrites of mitral cells synapse unto neighboring glomeruli independent of their odorant receptor identity.

In the mouse olfactory bulb, neural map topography is largely established by axon-axon interactions of olfactory sensory neurons (OSNs). However, to make the map functional, the OSNs must make proper connections to second-order neurons, the mitral cells. How do the mitral-cell dendrites find their partner glomeruli for synapse formation with OSN axons? Here, we analyze dendrite connections of mitral cells in various mutant mice in which glomerular formation is perturbed.

Sema7A/PlxnCl signaling triggers activity-dependent olfactory synapse formation.

In mammals, neural circuits are formed based on a genetic program and further refined by neuronal activity during the neonatal period. We report that in the mouse olfactory system, the glomerular map is not merely refined but newly connected to second-order neurons by odorant-receptor-derived neuronal activity. Here, we analyzed a pair of molecules, Sema7A, expressed in olfactory sensory neurons (OSNs) in an activity-dependent manner, and PlxnC1, localized to dendrites of mitral/tufted (M/T) cells in the first week after birth.

Genetic analysis of non-hydrogen sulfide-producing Salmonella enterica serovar typhimurium and S. enterica serovar infantis isolates in Japan.

Whole-genome sequencing of non-H(2)S-producing Salmonella enterica serovar Typhimurium and S. enterica serovar Infantis isolates from poultry meat revealed a nonsense mutation in the phsA thiosulfate reductase gene and carriage of a CMY-2 β-lactamase. The lack of production of H(2)S might lead to the incorrect identification of S.

Deletion of the core-H region in mice abolishes the expression of three proximal odorant receptor genes in cis.

We have previously reported that a 2.1-kb homology (H) sequence, conserved between mouse and human, regulates the odorant receptor (OR) gene MOR28 in transgenic mice. Here, we narrowed down the essential sequences of the H to a core of 124 bp by using a transient expression system in zebrafish embryos.