Expression profiles of ndel1a and ndel1b, two orthologs of the NudE-Like gene, in the zebrafish

NudE-Like (NDEL1/NUDEL), through its interaction with LIS1 and DISC1, has been implicated in the etiology of neurological disorders such as lissencephaly and schizophrenia, respectively. Subsequently, a large portion of the research done on the function of NDEL1 has been specifically targeted to its role in brain development while ignoring its function in other developing and adult tissues. To begin a more global exploration of NDEL1's function, this study characterizes the developmental expression pattern of the NDEL1 orthologs in the zebrafish embryo. Our bioinformatic analyses identified two NDEL1 orthologs in the zebrafish, ndel1a and ndel1b. ndel1a is expressed predominantly in the anterior central nervous system (CNS), trigeminal ganglia, and eyes while ndel1b is expressed in the developing somites and, later, in the CNS. In addition to the spatial differences in their expression patterns, these genes are also individually regulated in their temporal expression. Both are expressed maternally but at later time-points there are subtle differences. ndel1a expression is lost between 6 and 12 hpf but then increases to a higher, near steady state, level from 72 to 120 hpf. ndel1b expression decreases from 3 to 36 hpf and subsequently increases from 36 to 120 hpf. The non-overlapping expression patterns of these two orthologs may indicate that they have split the functional role of the one NDEL1 gene present in mammalian species. The temporal and spatial regulation of these two orthologs will aid in the characterization of the multiple functions of this gene in both the developing and mature organism.