Expression pattern of lacZ reporter gene representing connexin36 in transgenic mice

Abstract

Targeted deletion of the connexin36 (Cx36) gene in the mouse genome leads to visual transmission defects, weakened synchrony of rhythmic inhibitory potentials in the neocortex, and disruption of gamma-frequency network oscillations. We have generated transgenic mice in which a reporter protein consisting of the exon1 coded N-terminal part of Cx36 fused to beta-galactosidase (N36-beta-gal) is expressed instead of Cx36. Here, we have used these mice for a detailed analysis of the reporter gene expression. By beta-gal staining of adult retina, we found expression of the lacZ reporter gene in the ganglion cell layer, in two rows of the inner nuclear layer, and in the photoreceptor layer. In the brain, beta-gal staining was present in gamma-aminobutyric acid (GABA)ergic neurons of the cerebellar nuclei, in non-GABAergic neurons of the inferior olive, in mitral cells of the olfactory bulb, and in parvalbumin-positive cells of the cerebral cortex. Outside the central nervous system, N36-beta-gal signals were detected in insulin producing beta-cells of the pancreas and in the medulla of the adrenal gland of adult Cx36(+/del[LacZ]) mice. This expression pattern suggests that Cx36 fulfills functional roles not only in several types of neurons in the retina and central nervous system but also in excitable cells of the pancreas and adrenal gland.

Connexins: Key Mediators of Endocrine Function

“…Chromaffin cells of the adrenal medulla are joined by Cx36-made gap junctions (93,111,322), which account for the cell-to-cell spreading of the [Ca 2ϩ ] i transients driven by action potentials (93,322,323). This spreading is enhanced after exposure of a few cells to nicotine, which also triggered the release of catecholamines, indicating that connexin signaling can amplify the secretion of epinephrine and norepinephrine induced by the synaptic activation of individual cells (322).…”

“…The insulin-producing ␤-cells of pancreatic islets are coupled exclusively by Cx36 channels in rodents and humans (111,478,479,538). Several lines of evidence, discussed in detail in section V, indicate that this protein and/or the ␤-to-␤-cell coupling it establishes is involved in the control of insulin secretion (19,71,334,335,339,376).…”

Connexin36 knockout mice display increased sensitivity to pentylenetetrazol-induced seizure-like behaviors

“…Many different connexin proteins are expressed in the various brain cell-types. Immunolabelling studies indicate that connexin36 (Cx36) is the predominant gap junction protein expressed in neurons (Condorelli, et al 2000, Degen, et al 2004, Rash, et al 2000, Sohl, et al 1998). Other connexins with minor expression in mouse neurons include connexin30.2 (Cx30.2) (Kreuzberg, et al 2008), and connexin45 (Cx45) (reviewed in Sohl, et al 2005).…”

Functional characterization of enzymes catalyzing ceramide phosphoethanolamine biosynthesis in mice

“…␤ -galactosidase staining was carried out according to Degen et al ( 38 ). Stained sections were mounted on glass slides (Menzel, Germany), dried on a heating plate at 37°C, and mounted with Entellan (Merck Millipore Chemicals, Germany).…”