Expr12324

In contrast to a previous report (Zhao and Emmons, 1995), LIN-32::GFP expression was not observed in the Rn ("ray precursor") cells. Instead, expression was first apparent in the anterior daughters of these cells, the Rn.a or "ray neuroblast" cells. In wild-type animals, these cells undergo two additional rounds of division to generate the four postmitotic ray cells. Unexpectedly, we found that LIN-32::GFP was asymmetrically distributed in these divisions. When Rn.a divides, LIN-32::GFP is initially detectable in both daughter cells. However, its expression is maintained only in the anterior daughter, Rn.aa, such that LIN-32::GFP becomes rapidly undetectable in its sister Rn.ap. This pattern is repeated in the division of Rn.aa: shortly after an initially similar distribution of LIN-32::GFP, Rn.aaa displays high LIN-32::GFP levels, whereas expression in its sister Rn.aap, fated to undergo programmed cell death, is weaker. Several hours later, LIN-32::GFP becomes undetectable in Rn.aaa itself, as this cell differentiates into an RnA neuron. Thus, LIN-32 expression becomes reiteratively restricted to the anterior daughter cell shortly after two successive cell divisions.

Expr9260

In the head of both males and hermaphrodites, the expression of the Ptbb-4::YFP transcriptional reporter was observed in many amphid neurons, likely ADL, AFD, ASE, ASG, ASH, ASJ, ASK, ASI, AWA, AWB, and AWC as judged by co-labeling with lipophilic dyes and/or cellular morphology. Other head neurons expressing Ptbb-4::YFP include the cephalic CEP neurons, the outer labial quadrant OLQ neurons, and the mechanosensory FLP neurons. In the midbody and tail, Ptbb-4::YFP expression was found in the PDE postdeirid neurons, PQR (a sensory neuron whose cilium is exposed to the pseudocoelomic fluid), and the phasmid neurons PHA and PHB. Ptbb-4::YFP was also expressed in all 18 ray neurons in the male, consistent with a previous report (Portman and Emmons 2004). Because of abundant ray neuron expression, Ptbb-4::YFP expression in male phasmid and hook neurons could not be reliably confirmed, although expression in these cells is not unlikely. We also observed Ptbb-4::YFP expression in the hermaphrodite HSN motor neurons, the vulval muscles, and several unidentified nonsensory neurons. Expression was also occasionally apparent in the amphid sheath (AMsh) and socket (AMso) glial cells.