Towards cracking the code: LIM protein complexes in the spinal cord

Combinatorial transcription codes are used widely in the developing nervous system to specify the development of many distinct cell types. Although this strategy maximizes the use of small numbers of proteins, the molecular basis for imposing specificity remains unclear. A recent study has addressed this question by demonstrating that the favoring of hexameric complexes of specific LIM homeodomain proteins over tetramers could dictate the choice between motor neuron versus interneuron fate.