Cell proliferation in the crypt.

Cell proliferation is evaluated with antibodies for Ki-67 antigen. Cells expressing Ldb1 (a–c) and Isl1 (d–f) are negatively stained by Ki-67 proliferation marker. a. Ldb1-expressing cells (green); b. Ki-67-expressing proliferative cells (red); c. Merge of a and b (x1000). d. Isl1-expressing cells (red); e. Ki-67-expressing cells (green); f. Merge of d and e (x1000). Arrows point on cells expressing either Ldb1 (a, b, c) or Isl1 (d, e, f). Nuclei are counterstained with DAPI (blue).