THE EXON-INTRON ORGANIZATION OF THE HUMAN X-LINKED GENE (FLN1) ENCODING ACTIN-BINDING PROTEIN-280

We have determined the exon-intron organization of the human X-linked gene (FLN1) encoding actin-binding protein 280 (filamin), a ubiquitous protein that plays an important role in the mechanochemical activitie s of cells through its association with actin filaments and membrane c omponents. The gene is composed of 47 exons spanning approximately 26 kb. The first and part of the second exon are untranslated. The actin- binding domain at the N-terminus is encoded by exons 2 to 5. The 96-am ino-acid repeats corresponding to the elongated rod backbone of the pr otein are encoded by the remaining 42 exons: size, location, and bound aries of the exons cannot be easily correlated with the repeated struc ture, while sequences interrupting the repeats (the two hinge segments preceding repeats 16 and 24 and the 8-amino-acid (aa) segment interru pting the 15th repeat) were encoded by separate exons, suggesting that they may be recent additions to the X-linked protein. The 8-aa segmen t is encoded by exon 29, which is alternatively spliced. (C) 1994 Acad emic Press,Inc.