Volume 114, Issue 5, Pages 878-882 (May 1998) A new source of cells contributing to the developing gastrointestinal tract demonstrated in chick embryos  Dale E. Bockman, G.S. Sohal  Gastroenterology  Volume 114, Issue 5, Pages 878-882 (May 1998) DOI: 10.1016/S0016-5085(98)70306-3 Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 1 Demonstration of labeling and emigration of cells from the neural tube. LZ-12 retrovirus, which labels nuclei, was injected into the lumen of experimental embryos on day 2. (A) Whole mounts harvested on day 3 show no labeling when the retrovirus is placed on top of the cranial neural tube in the control, whereas (B) labeled cells (arrows) are obvious in the ventral portion of the hindbrain neural tube on day 3 in an embryo given LZ-12. (C) Labeled cells (arrows) in the ventral neural tube (n) in a section through the hindbrain. (D) A whole mount showing a trail of labeled cells (arrows) associated with the vagus nerve (X) on day 4. (E) Histological section on day 4 shows labeled cells (arrows) remaining in the neural tube (n) and those that have migrated in association with the nerve and ganglion. (F) Labeled cells (arrows) in the vagus nerve on day 5 (original magnification: A and B, 100×; C, E, and F, 190×; D, 80×). Gastroenterology 1998 114, 878-882DOI: (10.1016/S0016-5085(98)70306-3) Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 2 Identification of labeled cells (progeny of ventral neural crest cells) in the (A and B) intestine and (C) stomach. Cells were labeled with LZ-14 retrovirus to show the cytoplasm and, therefore, their morphology. Specimens were harvested from 11-day-old embryos after labeling on day 2. Labeled smooth muscle cells (m) are evident in (A) a whole mount and (B) a histological section of the intestine, and (C) in a section of stomach. Labeling of smooth muscle cells was observed in six different embryos (original magnification: A, 100×; B, 190×; C, 200×). Gastroenterology 1998 114, 878-882DOI: (10.1016/S0016-5085(98)70306-3) Copyright © 1998 American Gastroenterological Association Terms and Conditions

Fig. 3 Confirmation of the smooth muscle nature of labeled cells and exclusion of their origin from neural crest. (A) Smooth muscle cells in the circular layer, including labeled cells (m), are positive for smooth muscle α-actin. This micrograph is of the section shown in Figure 2B after immunolocalization with anti–smooth muscle α-actin. N, region of developing enteric nervous system (compare with B). (B) Labeled smooth muscle cells (m) are negative for HNK1, a commonly used marker for neural crest cells. The developing enteric nervous system (N) is positive, indicating a successful immunocytochemistry procedure (original magnification: A, 300×; B, 375×). Gastroenterology 1998 114, 878-882DOI: (10.1016/S0016-5085(98)70306-3) Copyright © 1998 American Gastroenterological Association Terms and Conditions