Fluorescent Proteins Expressed in Mouse Transgenic Lines Mark Subsets of Glia, Neurons, Macrophages, and Dendritic Cells for Vital Examination

Abstract

To enable vital observation of glia at the neuromuscular junction, transgenic mice were generated that express proteins of the green fluorescent protein family under control of transcriptional regulatory sequences of the human S100B gene. Terminal Schwann cells were imaged repetitively in living animals of one of the transgenic lines to show that, except for extension and retraction of short processes, the glial coverings of the adult neuromuscular synapse are stable. In other lines, subsets of Schwann cells were labeled. The distribution of label suggests that Schwann cells at individual synapses are clonally related, a finding with implications for how these cells might be sorted during postnatal development. Other labeling patterns, some present in unique lines, included astrocytes, microglia, and subsets of cerebellar Bergmann glia, spinal motor neurons, macrophages, and dendritic cells. We show that lines with labeled macrophages can be used to follow the accumulation of these cells at sites of injury.

Identity, developmental restriction and reactivity of extralaminar cells capping mammalian neuromuscular junctions

“…First, double immunostaining with 2166 antibody and antibodies for either GFAP or nestin showed no colocalisation, demonstrating that NMJ-capping cells are not terminal Schwann cells. We confirmed this by 2166 immunostaining in S100-eGFP mice (Zuo et al, 2004) in which all myelinating and terminal Schwann cells are endogenously fluorescent (Fig. 2A).…”

Reinnervation of the tibialis anterior following sciatic nerve crush injury: A confocal microscopic study in transgenic mice

“…GFP signal intensity is proportional to S100B promoter activity in S100-GFP mice (Zuo, et al, 2004), and signal changes are noted in all mice following sciatic nerve crush injury. In uninjured control animals, TSCs express GFP with significantly (p<0.001) more intensity (852.2 ± 401.5 gray scale units) than SCs in the periphery (252.1 ± 102.3 gray scale units).…”

“…Additionally, the distribution and morphology of mature, differentiated SCs is assessed in S100-GFP mice, (generous gift from Dr. W. Thompson, University of Texas, Austin, now available through Jackson Laboratories) which utilize the S100B promoter to drive GFP expression (Allore RJ, 1990, Castets F, 1997, Jiang H, 1993, Ludwin SK, 1976, Stefansson K, 1982, Zuo, et al, 2004. S100-GFP mice (n=15), are also bred to thy1-CFP(23) mice (Jackson Laboratories) to produce thy1-CFP(23)/S100-GFP offspring that express cyan fluorescent protein (CFP) in their axons and GFP in their SCs (Feng, et al, 2000) (n=10).…”

“…More direct in vivo evaluation of axonal regeneration and motor endplate reinnervation can be done using recently developed transgenic mice whose axons (Feng, et al, 2000), or Schwann cells (SCs) (Zuo, et al, 2004), constitutively express chromophores. Direct evaluation of axons and SCs in vivo has primarily been performed in small, thin muscles like the sternomastoid, or platysma, where labeled axons of the spinal accessory nerve, or cervical branch of the facial nerve, can be serially evaluated (Feng, et Unfortunately, small caliber nerves, like the spinal accessory and delicate facial nerve branches, are not easy to surgically manipulate.…”

Two-photon imaging of synaptic plasticity and pathology in the living mouse brain

“…60 Furthermore, it is not known what role they play in the process of amyloid deposition. With the availability of mice that express fluorescence in microglia 61 or astrocytes, 62 it should be possible to simultaneously image with TPM amyloid plaques, microglia, and neuronal structures. 63 These types of studies are likely to provide a wealth of information regarding the spatio-temporal relation between plaque formation, microglia migration around plaques, and the resulting synaptic pathology.…”