The mouse gap junction gene connexin29 is highly expressed in sciatic nerve and regulated during brain development.

A novel mouse gap junction gene, coding for a presumptive protein of 258 amino acids (molecular mass: 28 981 Da), has been designated connexin29. This single copy gene was mapped to distal mouse chromosome 5 and shows 75% sequence identity to a human connexin30.2 sequence in the database. Connexin29 mRNA (4.4 kb) is highly expressed in mouse sciatic nerve and less abundant in spinal cord as well as in adult brain, where it increased 12-fold between day 7 and 14 post partum. Our expression data suggest that the new connexin gene is active in myelin-forming glial cells.

Connexin genes in the mouse and human genome.

Gap junctions serve for direct intercellular communication by docking of two hemichannels in adjacent cells thereby forming conduits between the cytoplasmic compartments of adjacent cells. Connexin genes code for subunit proteins of gap junction channels and are members of large gene families in mammals. So far, 17 connexin (Cx) genes have been described and characterized in the murine genome. For most of them, orthologues in the human genome have been found (see White and Paul 1999; Manthey et al. 1999; Teubner et al. 2001; Söhl et al. 2001). We have recently performed searches for connexin genes in murine and human gene libraries available at EMBL/Heidelberg, NCBI and the Celera company that have increased the number of identified connexins to 19 in mouse and 20 in humans. For one mouse connexin gene and two human connexin genes we did not find orthologues in the other genome. Here we present a short overview on distinct connexin genes which we found in the mouse and human genome and which may include all members of this gene family, if no further connexin gene will be discovered in the remaining non-sequenced parts (about 1-5%) of the genomes.