The rearrangement test gene pHRD (High frequency deletional rearrangement) construct contained the E. coli gpt coding region under transcriptional control of the mouse metallothionein 1 promoter (PMT) and mouse immunoglobulin heavy-chain enhancer (EnH), and an insert consisting of a portion of the rat preproinsulin gene (including its initiation codon) flanked on the 5' side by a V kappa heptamer/nonamer and on the 3' side by a J kappa nonamer/heptamer. (J:134860)