Isolation of a mouse brain cDNA expressed in developing neuroblasts and mature neurons

A previously uncharacterized 4.5-kb mouse cDNA clone, designated mc7, was i solated and found to be predominantly expressed in brain. This cDNA predict s a 1035-bp open reading frame that encodes for a 345-amino acid polypeptid e especially rich in glutamic acid residues located in the region from resi dues 80 to 174. Computational analysis revealed among other features, putat ive zinc-finger motifs and coiled-coil regions. The corresponding mc7 gene is detected in mouse, rat, pig and human genomes. In mouse the mc7 mRNA is expressed predominantly in brain and to a much lesser extent in kidney, lun g and spleen. In brain it is delectable as early as embryonic day 14 while it is retained in the adult. In situ hybridization studies revealed that mc 7 mRNA is widely, albeit unevenly, expressed in neurons throughout the adul t brain. Developmental in situ hybridization studies in the cerebellar cort ex demonstrated that at postnatal day 5 mc7 mRNA is mainly expressed in neu roblasts of the external granular layer and in developing neurons of the in ternal granular layer. Some staining is also present in purkinje cells beco ming particularly pronounced at postnatal day 10, the time of arborarizatio n of their dendritic tree. In the adult cerebellar cortex expression is mai nly confined in purkinje cells and to a lesser extent in granule neurons. T he early expression of mc7 in neuroblasts and developing neurons as well as its retention in a wide variety of mature neurons suggest that it may play a role in the process of differentiation and maturation of these cells in the brain. (C) 2001 Elsevier Science B.V. All rights reserved.