Figure 1.6-A. The cystic fibrosis transmembrane conductance regulator 
(CFTR) gene, mRNA and predicted protein product. The CFTR gene is comprised 
of 27 exons (denoted 1-5, 6a, 6b, 7-13, 14a, 14b, 15-16, 17a, 17b, 18-24) 
spread out over 250 kb of chromosome 7. The mRNA is 6.5 kb, including 4.5 
kb of coding exons and a 2 kb untranslated 3' tail (not shown) . The pre- 
dicted CFTR protein has 5 major domains as indicated (see Figure 1.6-B for 
details concerning the structure and function of the CFTR protein) . Also 
indicated is the location in exon 10 of the common AF508 mutation (see 
text, section 1.6). 
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