Targeting strategy for SP-D gene disruption and
confirmation of the expected null mutation by genotype analysis.
(a) The thin line depicts the mouse SP-D gene, with the
eight exons indicated by boxes. Pgk-neo replaced all of exon 2 that
contains the translation start site for SP-D. The 600-bp probe used for
Southern blot screening is located 5′ to the targeting vector. B,
BstXI; r, EcoRI; H,
HindIII; X, XbaI. (b)
Southern blot of tail genomic DNA from wild type (+/+), heterozygous
(+/−), and SP-D null (−/−) mice and embryonic stem clone DNA
after BstXI digestion. The 6.2-kb BstXI
band is the normal allele and the 3.1-kb BstXI band the
mutant allele.