Illustration of human IL-10 gene structure and protected fragment generated in RNAse protection assays. (A) This diagram depicts the genomic structure of the human IL-10 gene and delineates unique restriction enzyme sites used to generate template cDNA for RNAse protection assays. (B) Probes generated for RNAse protection assays are as follows: (1) a completely processed 201-bp PvuII/Cla I fragment including a portion of exon II, all of exon III, and a portion of exon IV, and three incompletely processed protected fragments including a 197-bp portion of exon II and the complete exon III, a 157bp fragment including all of exon III and a portion of exon IV, and a 153-bp fragment consisting of exon III only. The probe used in RNAse protection half-life assays (2) was a 155-bp BstEII/Cla I fragment which included the majority of exon III and a small portion of exon IV.