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Abstract: The Ebf transcription factors play important roles in the developmental processes of many tissues. We have shown previously that four members of the Ebf family are expressed during mouse retinal development and are both necessary and sufficient to specify multiple retinal cell fates. Here we describe the changes in cell differentiation and retinal ganglion cell (RGC) projection in Ebf1 knockout mice. Analysis of marker expression in Ebf1 null mutant retinas reveals that loss of Ebf1 function causes a significant increase of Müller cells. Moreover, there is an obvious decrease of ipsilateral and retinoretinal projections of RGC axons at the optic chiasm, whereas the contralateral projection significantly increases in the mutant mice. These data together suggests that Ebf1 is required for suppressing the Müller cell fate during retinogenesis and important for the correct topographic projection of RGC axons at the optic chiasm. [Copyright &y& Elsevier]

Abstract: Hemokinin-1, encoded by the TAC4 gene, is a tachykinin most closely related to substance P. Previous studies have shown that TAC4 distinguishes itself from other tachykinins by its predominantly non-neuronal expression profile, particularly in cells of the immune system. Here we report for the first time that the highest levels of TAC4 expression are found in the olfactory epithelium. Furthermore, we identify olfactory neuron-specific transcription factor (Olf-1), also known as early B-cell factor (EBF), as a novel regulator of TAC4 expression. EBF present in the olfactory epithelium and in B cells binds to two sites in the TAC4 promoter and modulates expression in developing B cells. Our findings suggest a role for TAC4 in cell differentiation, and represent a regulatory bridge between the nervous system and the immune system. [Copyright &y& Elsevier]

Early B-cell factor 2 (EBF2) is one of four mammalian members of an atypical helix-loop-helix transcription factor family (COE). COE proteins have been implicated in various aspects of nervous and immune system development. We and others have generated and described mice carrying a null mutation of Ebf2, a gene previously characterized in the context of Xenopus laevis primary neurogenesis and neuronal differentiation. In addition to deficits in neuroendocrine and olfactory development, and peripheral nerve maturation, Ebf2 null mice feature an ataxic gait and obvious motor deficits associated with clear-cut abnormalities of cerebellar development. The number of Purkinje cells (PCs) in the Ebf2 null is markedly decreased, resulting in a small cerebellum with notable foliation defects, particularly in the anterior vermis. We show that this stems from the defective migration of a molecularly defined PC subset that subsequently dies by apoptosis. Part of the striped cerebellar topography is disrupted due to cell death and, in addition, many of the surviving PCs, that would normally adopt a zebrin II-negative phenotype, transdifferentiate to Zebrin II-positive, an unprecedented finding suggesting that Ebf2 is required for the establishment of a proper cerebellar cortical map. [ABSTRACT FROM AUTHOR]