Molecular characterization of a new member of the protein 4.1 family (brain 4.1) in rat brain

In addition to the well-known erythroid 4.1 gene, two human genes (KIAA0338 and 4.1G) have recently been identified as members of the protein 4.1 fami ly of genes. We compared the expression levels of these three genes and fou nd that the KIAA0338 gene was predominantly expressed in human brain. To fu rther characterize this novel protein 4.1, called brain 4.1, we isolated ra t brain 4.1 cDNA and analyzed its gene products in rat brain. The results i ndicated that the mRNA and protein products of the brain 4.1 gene were more abundant in brain compared to any other tissues examined. The brain 4.1 mR NA appeared as multiple bands with estimated sizes of 3.9 kb, 6.2 kb and 8. 7 kb on RNA blotting analysis, and was found to consist of various alternat ive forms as reported previously for the erythroid 4.1 gene. As for the bra in 4.1 gene product, many isoforms discernible by immunoblotting analysis w ere also observed depending on the tissue type and the brain region. The ex istence of multiple forms of the brain 4.1 implies that it has multiple and diverse functions like the erythroid 4.1 gene product. (C) 1999 Elsevier S cience B.V. All rights reserved.