First detected at comma stage in pharyngeal primordium as pharyngeal muscles begin terminal differentiation. Strong expression is detected in most cells during late embryogenesis when cells are either differentiating or undergoing cell cycle arrest prior to hatching. At hatching and in L1 animals maintained in absence of food expression detected in Q, M, Z1, Z4 and V cells. Expression in these cells fades after feeding when cell division resumes. Strong expression is observed in many postmitotic neurons and muscle cells. Stronger expression is detected in newly differentiated cells and then gradually decreases.
cki-1 also expressed in dauer larvae. 1. Lateral hyodermal V lineage: V cells show strong expression until they divide in the mid L1 (fluorescence decreases significantly). Seam cells express at quite high levels during resting phases between molts and at a reduced level during division. Expression increases at L4 (coincident with seam cell terminal differentiation). 2. sex myoblasts (SM)lineage: High level of expression observed during SM migration, reduced during SM division and high again as the sex muscles differentiate. 3. P lineage: L1-molt progeny of Pn.a neuroblasts express high levels of
cki-1::gfp. 4. Somatic gonad: Expression in Z1 and Z4 diminishes prior to cell division in mid-L1. Strong expression in Z1.aa and Z4.pp, the distal tip cells, beginning in L2, undetectable in the rest of Z1/Z4 lineage until the late L3 and early L4. Expression in somatic gonad increases dramatically at the onset of terminal differentiation. 5. Intestine: After L1-molt expression in intestine is seen throughout the larval stages 6. Vulva precursor cells:
cki-1::gfp expression first detected in vulva precursor cells (VPCs) in late L1 or early L2 and peaks at L2 molt.