Schematic diagram of the exon and intron structures for the merlin genes of various species. The horizontal line depicts the merlin gene with its size indicated in base pairs (bp) on the right. The upright boxes represent exons. The lengths of the merlin mRNA sequences available in the database are shown in nucleotides (nt) and the lengths of the predicted merlin proteins are also indicated in amino acids (aa). The indicated human NF2 mRNA refers to the longest, full-length transcript identified, which contains a long 3' untranslated region . Two major NF2 isoforms I and II are produced via alternative splicing and the lengths of their protein products are shown with that of isoform I indicated in the parentheses. It should be noted that Northern blot analysis detected the rat and mouse NF2 mRNAs of about 4.5 kb, indicating that the sizes of the rodent NF2 mRNAs shown here are not full-length. The asterisk (*) denotes the exon-intron structure of Brugia malayi predicted from this study.