Figure 1.

ACE expression in ACE 10/10 mice. A: The top of the figure shows the wild-type organization of the ACE locus. Both the somatic ACE promoter and the testis ACE promoter are indicated with arrows. In the ACE 10/10 gene (bottom), homologous recombination was used to position a neomycin resistance cassette (Neo^R) and a 7.2-kb c-fms promoter cassette such that the structural portion of the ACE gene is now under the control of the c-fms promoter. B: ACE activity was measured in organ homogenates of wild-type (w/w), heterozygous (wt/10), and ACE 10/10 mice. ACE activity is expressed as units per milligram total solubilized protein. The data are the group means ± SEM of 6 to 10 individual mice. C: The top panel shows tissue homogenates from wild-type (WT), heterozygous (HZ), and ACE 10/10¹⁰ mice that were studied by Western blot analysis using a rabbit anti-ACE antibody. Somatic ACE (sACE) is a band of about 170 kd, whereas testis ACE (tACE) is about 100 kd. The bottom panel shows ACE Western blot analysis of peritoneal macrophages collected after thioglycollate injection. In contrast to wild type, ACE 10/10 macrophages express abundant ACE. D: FACS was performed on white cells from the blood and peritoneal lavage of wild-type and ACE 10/10 mice. Cells were stained with a polyclonal rabbit anti-ACE antibody and costained with antibody against CD3, B220, Gr-1, or F4/80. The upper portion of the figure shows that macrophages (F4/80 bright cells) and neutrophils (Gr-1 bright cells) from ACE 10/10 mice express approximately 16- and fourfold more ACE (as estimated by mean fluorescent activity) than these cells from wild-type mice. The lower portion of the figure shows a histogram of the ACE staining for B cells (B220 bright), T cells (CD3 bright), macrophages, and neutrophils. The solid line shows cells from ACE 10/10, whereas the dotted line shows equivalent data from wild-type mice. Similar data were found in cells from spleen and bone marrow.