TITLE
Opn4tauLacZ/+ Knock-in Mice
CASE NUMBER: C13016
ABSTRACT
The primary circadian pacemaker, in the suprachiasmatic nucleus (SCN) of the mammalian brain, is photoentrained by light signals from the eyes through the retinohypothalamic tract. Retinal rod and cone cells are not required for photoentrainment. Recent evidence suggests that the entraining photoreceptors are retinal ganglion cells (RGCs) that project to the SCN. The visual pigment for this photoreceptor may be melanopsin, an opsin-like protein whose coding messenger RNA is found in a subset of mammalian RGCs. By cloning rat melanopsin and generating specific antibodies, we show that melanopsin is present in cell bodies, dendrites, and proximal axonal segments of a subset of rat RGCs. In mice heterozygous for tau-lacZ targeted to the melanopsin gene locus, beta-galactosidase–positive RGC axons projected to the SCN and other brain nuclei involved in circadian photoentrainment or the pupillary light reflex.
FEATURES
Tau-lacZ was targeted to the Opn4 locus in a knock out strategy to study the role of the Opn4 locus.
To examine the axonal projections of the melanopsin-positive RGCs, Johns Hopkins researchers targeted tau-lacZ into the melanopsin gene locus in mouse. Tau-lacZ codes for a protein composed of the beta-galactosidase enzyme fused to a signal sequence from tau (an actin-associated protein), which allows the fusion protein to be preferentially transported down the axon to the presynaptic terminal.
STAGE OF DEVELOPMENT
Tangible material, Opn4tauLacZ/+ Knock-in Mice
ASSOCIATED PUBLICATIONS
- PMC2885915 -
TECHNOLOGY CLASSIFICATION
Primary Category: Discovery/Research Tools
Primary Subcategory: In Vivo Research Tool
