Map of the deletions of 5′HS1 and 5′HS4.

(A) Modifications of 5′HS1 as labeled. The numbered boxes are 5′HSs; the solid boxes are Ey; the hatched boxes are the probe used for Southern analysis. B denotes BglII sites, and Sp denotes SpeI. Numbers above the map are the expected restriction fragment sizes. (B) Southern blot demonstrating targeted deletions of 5′HS1. Genotypes of the mice are as follows: lane 1, Δ1neo/Δ1; lane 2, Δ1neo/D; and lane 3, Δ1/D. (C) Modifications of 5′HS4 as labeled. Elements are as in panel A. S denotes SphI sites. (D) Southern blot demonstrating targeted deletions of 5′HS4. Genotypes are as follows: lane 1, S/S; lane 2, Δ4neo/Δ4neo; lane 3, Δ4neo/S; lane 4, Δ4/S; and lane 5, Δ4/Δ4.