Intestine development

The C. elegans intestine is attached to the posterior pharynx and extends the length of the worm, ending at the rectum. This major organ of the worm consists of 20 large, polyploid epithelial cells arranged in pairs, forming a tube. The intestine is responsible for food digestion, nutrient absorption, and synthesizing and storing macromomlecules such as fat droplets and birefringent gut granules. The intestine also plays major roles in the rhythmic behavior of the defecation cycle as well as stress responses and lifespan.

Pharyngeal development

The progression of events that leads to the formation of a functional pharynx, the feeding organ just posterior to the mouth or buccal cavity and anterior to the intestine. In C. elegans the pharynx is divided into anterior and posterior regions. The anterior region includes the corpus (procorpus and metacorpus - first bulb) and the posterior region includes the isthmus and terminal bulb (second bulb). Cells first commit to a pharyngeal fate during gastrulation. Establishment of this cell fate is directed by PHA-4, a FoxA transcription factor and four Tbox transcription factors, TBX-2, -35, -37, and -38. The linear gut tube is formed during later embryogenesis. Cell fate commitment during pharyngeal development occurs through a combination of positive feedback loops, positive autoregulation and repression of alternative fates. Other steps in the development of this organ include tissue morphogenesis, muscle differentiation and establishment and maintenance of apical/basal polarity.