Figure 1.

Lmo4 is abundantly expressed in the lobuloalveolar units during pregnancy. (A) A single layer of ductal epithelium expressing Lmo4 transcripts is evident in the adult mammary gland. RNA expression was assessed by in situ hybridization by using sense (control) and antisense digoxigenin-labeled riboprobes corresponding to the full-length mouse Lmo4 sequence. Young adult virgin, 12-day pregnant, 2-day lactating, and 4-day involuting mammary glands were analyzed. The sense probe was hybridized to sections of 3-day involuting (shown), and to sections of lactating and pregnant mammary glands. (Original magnification ×50.) (B) Northern blot analysis of mammary glands from virgin, pregnant, lactating, and force-weaned (involuting) mice. Filters containing 20 μg of total RNA were hybridized with a mouse Lmo4 probe. The lower molecular weight bands may represent either an alternatively spliced variant of Lmo4 RNA or a cross-hybridizing species. The ethidium bromide-stained gel showing 28S and 18S ribosomal RNA provides a loading control.