Identification and Developmental Expression of the Zebrafish ZGC:154061 Gene, a Conserved Yet Uncharacterized Maternally Expressed MEIS2 Linked Gene

We have identified a novel and previously undescribed gene, zgc:154061, located directly downstream of the zebrafish meis2.2 gene. We have identified putative orthologs of this gene in all animals that we have been able to examine. The zgc:154061 gene and its vertebrate orthologs are organized in a convergently transcribed manner with respect to the Meis2 gene in all species we have examined (meis2.2 in teleosts). It appears that the homologs of Meis and zgc:154061 are also linked in amphioxus and sea urchins but that this linkage is not present in urochordates, nor in protostomes. During zebrafish development, transcripts of zgc:154061 are observed in every cell of the embryo from the earliest stage through the shield stage indicating this gene is a maternal transcript since its expression precedes the activation of the zygotic genome at the midblastula transition. Expression of zgc:154061 gradually decreases from its peak value at 0 hpf until 8 hpf and then is observed to be activated again at 12 hpf throughout the neural tube before becoming restricted to the retina and tectum opticum by 48 hpf.