PROSITE documentation PDOC01044

COE family signature

The independent cloning of rodent EBF/Olf-1 and Drosophila Collier has defined a family of transcription factors, the Collier or COE family [1]. COE proteins have various functions in different organisms. Proteins currently known to belong to this family are listed below:

• Mammalian COE1 (OLF-1; EBF-1; OE-1), COE2 (EBF-2; OE-3) and COE3 (EBF-3; OE-2).
• Xenopus XCOE2 and XCOE3.
• Zebrafish ZCOE2.
• Drosophila Collier.
• Caenorhabditis elegans unc-3.

In mouse, COE1 has a role in B-cell differentiation, and could also perform a role in neuronal differentiation. All three COE are expressed in immature olfactory neuronal precursors and mature olfactory neurons as well as in developping nervous system during embryogenesis.

In Drosophila, Collier is involved in the formation of the embryonic somatic muscle DA3, in the patterning of the wing by mediating Hedgehog activity. It could also act as a second-level regulator in the patterning of embryonic head.

In Xenopus, XCOE2 is expressed in precursors of primary neurons, and may play a pivotal role in the transcriptional cascade specifying primary neurons in embryo. It promotes neuronal differentiation by activating XNeuroD expression.

In Zebrafish, ZCOE2 is expressed in a subset of primary neuroblasts in the spinal cord and at later stages is a marker of the olfactory placodes.

Caenorhabditis elegans mutants for unc-3 move abnormally suggesting that unc-3 might regulate expression of genes involved in growth cone pioneering long the ventral cord or in fasciculation.

As a signature for these proteins we selected a conserved region located in a domain thought to be part of the DNA-binding region. The signature pattern includes four conserved cysteines that could be part of a zinc-finger motif.