Structure and analysis of the human SCL YAC transgenes.

(A) Diagram of the 130-kb YAC containing the human SCL gene together with part of the SIL gene and the completeMAP17 gene. A fine detail map of the modified SCLlocus is shown together with the location of the IRES-nls-lacZ cassette (hatched box) within the 3′ UTR of exon 6 (open box). Numbered horizontal lines indicate the restriction fragments assessed by Southern analysis (Table 1). (B) Southern hybridization of tail DNA from 5 lines together with a nontransgenic control mouse using equimolar concentrations of size matched probes for lacZ (transgene specific) and murine scl 3′ UTR (mouse specific). Transgene copy numbers were calculated with respect to the endogenous mousescl gene.