Visualization of β-galactosidase by enzyme and immunohistochemistry in the olfactory bulb of transgenic mice carrying the LacZ transgene

Gabriela Sekerková, Zoya Katarova, Ferenc Joó, Joachim R. Wolff, Simona Prodan, Gábor Szabó*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


In the olfactory bulb (OB) of a transgenic mouse line that carries the bacterial LacZ gene under the control of the 5'-regulatory region of the GAD67 gene, expression of the β-galactosidase was confined almost exclusively to the non-GABAergic mitral and tufted cells. By light microscopy, enzyme histochemistry showed strong staining in the cell bodies and faint diffuse staining in the axons and dendrites. With immunohistochemistry for β-galactosidase the entire cytoplasm, including the axons and dendrites, was strongly stained. By electron microscopy, β- galactosidase enzyme histochemistry resulted in a sub-microscopic reaction product that was diffusely distributed in the cytoplasm of neurons. In addition, largo deposits of the reaction product were also seen attached to the cytoplasmic side of the membranes. In contrast, when the intracellular localization of β-galactosidase was determined by immunohistochemistry, homogeneous cytoplasmic staining was obtained that filled the entire cytoplasm including the terminal dendrites and fine axons. Therefore, synaptic contacts of the β-galactosidase-positive output neurons with other β-galactosidase-negative neuronal cells were readily recognized in the OB. As we demonstrated, transgenic mouse lines expressing the LacZ reporter gene in a well-defined neuronal subpopulation can be used to follow β- galactosidase-positive neurons and to directly identify their synaptic connections.

Original languageEnglish (US)
Pages (from-to)1147-1155
Number of pages9
JournalJournal of Histochemistry and Cytochemistry
Issue number8
StatePublished - Aug 1997


  • GAD-LacZ fusion protein
  • Neuronal labeling
  • Olfactory system
  • Output neurons
  • Transgenic expression

ASJC Scopus subject areas

  • Anatomy
  • Histology


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