• cre loxp system
• mosaic
• pten ko
• hyperexcitability

The mTOR signalling pathway is an essential biochemical hub since it regulates central cellular aspect such as the cell growth, protein synthesis and homeostasis.
One of its main regulators is PTEN: briefly, this protein acts as a negative regulator of mTOR pathway, keeping under control the PIP3 concentration by its phosphatase activity.
PTEN is known to be implicated in tumor suppression and it has a great impact in different aspects of neuronal development such as the correct neuron positioning, the dendritic development and the synapse formation.
In this study we evaluated the impact of PTEN KO sparse mosaic in the late brain development by exploiting Beatrix, a biotechnological tool we developed for the generation and revelation of genetic mosaics, in combination with the in utero electroporation on PTENflox mice.
Beatrix is a plasmid able to create a tunable sparse mosaic. It works thanks to the CRE-LoxP system and a double reporter system: the mutated and healthy cells are labelled with GFP and dsRed respectively. In our case that means that green labelled cells are knocked out for PTEN gene while the red one maintain their original WT genotype.
By comparing the morphological and functional characteristics of the Pten KO population with respect to the WT cells we assessed an increased in soma and dendrites size and shape of the mutated cells. The layering of the Pten KO cells is also impaired.
From the functional point of view, in the mosaic we found an impaired excitation-inhibition balance (expected by the morphological analysis), assessed by LFP recording and spine motility analysis.