Green fluorescent protein expression and colocalization with calretinin, parvalbumin, and somatostatin in the GAD67-GFP knock-in mouse

J Comp Neurol. 2003 Dec 1;467(1):60-79. doi: 10.1002/cne.10905.


Gamma-aminobutyric acid (GABA)ergic neurons in the central nervous system regulate the activity of other neurons and play a crucial role in information processing. To assist an advance in the research of GABAergic neurons, here we produced two lines of glutamic acid decarboxylase-green fluorescence protein (GAD67-GFP) knock-in mouse. The distribution pattern of GFP-positive somata was the same as that of the GAD67 in situ hybridization signal in the central nervous system. We encountered neither any apparent ectopic GFP expression in GAD67-negative cells nor any apparent lack of GFP expression in GAD67-positive neurons in the two GAD67-GFP knock-in mouse lines. The timing of GFP expression also paralleled that of GAD67 expression. Hence, we constructed a map of GFP distribution in the knock-in mouse brain. Moreover, we used the knock-in mice to investigate the colocalization of GFP with NeuN, calretinin (CR), parvalbumin (PV), and somatostatin (SS) in the frontal motor cortex. The proportion of GFP-positive cells among NeuN-positive cells (neocortical neurons) was approximately 19.5%. All the CR-, PV-, and SS-positive cells appeared positive for GFP. The CR-, PV, and SS-positive cells emitted GFP fluorescence at various intensities characteristics to them. The proportions of CR-, PV-, and SS-positive cells among GFP-positive cells were 13.9%, 40.1%, and 23.4%, respectively. Thus, the three subtypes of GABAergic neurons accounted for 77.4% of the GFP-positive cells. They accounted for 6.5% in layer I. In accord with unidentified GFP-positive cells, many medium-sized spherical somata emitting intense GFP fluorescence were observed in layer I.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Calbindin 2
  • Central Nervous System / chemistry*
  • Gene Expression
  • Glutamate Decarboxylase / analysis*
  • Glutamate Decarboxylase / genetics
  • Green Fluorescent Proteins
  • Immunohistochemistry
  • In Situ Hybridization
  • Isoenzymes / analysis*
  • Isoenzymes / genetics
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism*
  • Mice
  • Mice, Neurologic Mutants
  • Motor Cortex / chemistry
  • Neurons / chemistry
  • Parvalbumins / analysis*
  • S100 Calcium Binding Protein G / analysis*
  • Somatostatin / analysis*
  • gamma-Aminobutyric Acid*


  • Calb2 protein, mouse
  • Calbindin 2
  • Isoenzymes
  • Luminescent Proteins
  • Parvalbumins
  • S100 Calcium Binding Protein G
  • Green Fluorescent Proteins
  • Somatostatin
  • gamma-Aminobutyric Acid
  • Glutamate Decarboxylase
  • glutamate decarboxylase 1