The present disclosure provides a method of directly converting a stem cell into a lineage specific cell, comprising the steps of a) transfecting a stem cell with at least one expression vector comprising i) one or more cell lineage reprogramming factors operably linked to an inducible promoter and ii) a selection marker; and b) inducing the transfected stem cell from stem a) with an inducing agent to directly convert said stem cell into a lineage-specific cell. Particularly exemplified are methods of transfecting a stem cell with SA-ASCL1 (phospho-mutant), DLX2, LHX6 and miR-9/9*-124 linked to a doxycycline inducible promoter to convert the stem cell into an inhibitory neuron and transfecting with NeuroD2 linked to a doxycycline inducible promoter to convert a stem cell into an excitatory neuron. Methods of screening one or more factors and/or one or more genetic mutations that modulate a pre-selected activity of the lineage specific cell, kits and directly convertible stem cells obtained using method of the invention are also provided.