Table 1 Comparison of phenotypic abnormalities observed in gene targeted β3 gene knockout mice
Phenotype | Global knockout | Pan-neuronal knockout* | Forebrain selective knockout* |
|---|---|---|---|
Time course of gene inactivation | Embryonic day 0 [18] | ~Embryonic day 12.5+ | ~2 weeks postnatal |
Tissue specificity | All cells [18] | Most neurons | Primarily forebrain neurons |
Viability | ~90% die as neonates [18] | ~61% die as neonates | ~30% die at 15–25 days of age |
Palate | ~55% with cleft [18]* | Normal | Normal |
Overt behavior | Hyperactive; hyperresponsive [3, 18] | Normal | Moderate hyperactivity; jumpy |
Locomotor activity | Increased [3] | Not tested | Increased |
Motor coordination | Impaired [3] | Not tested | Not tested |
Seizure-like activity | Multiple seizure types [3] | None observed | Occasional absence-like and convulsive seizures |
EEG | Abnormal [3, 18] | Not tested | Not tested |
Foot clasping | Present [18] | Absent | Absent |
Fertility | Normal [18] | Normal | Reduced |
Maternal behavior | Impaired [18] | Normal | Impaired |
Body size | Runted until weaning but most attain normal size by adulthood [18] | Normal | Some become obese |
Food intake | Not tested | Not tested | Increased |
Etomidate LORR | Reduced [33] | Reduced | Reduced |
Ethanol LORR | Normal [33] | Normal | Normal |
Learning and memory | Impaired [3] | Not tested | Normal |
Rest-activity cycles | Disturbed [3] | Not tested | Not tested |