Consistent with this, and in agreement with the frequent absence of the crystalline granule core seen ultrastructurally, the granule constituent MBP-1 was much reduced relative to WT in CF null in vitro generated eosinophils (Figure 4B) although MBP-1 mRNA transcripts measured by semiquantitative PCR were essentially the same in both cell types (data not shown). Here, ENO1 is linked to cystic fibrosis.