In order to gain insights into the regulatory control of neuronal diversity in the mammalian olfactory system, we have identified the transcriptional profile of individual olfactory neurons. A single cell microarray strategy was performed to search for candidate genes involved in the molecular specification of dorso-ventral zones of olfactory receptor (OR) expression. Several transcripts were identified that display differential expression in distinct OR zones, including a novel family of genes, the Lozenge-like (Lzl) genes which share sequence consensus motifs with Lozenge, a transcription factor involved in the patterning of the Drosophila olfactory and visual systems.