lin-14 protein is first observed in embryos at ~7 hours after fertilization where most intense staining is seen in intestinal and hypodermal nuclei. ~9 h after fertilization, additional weak staining is observed.
lin-14 protein is expressed at high level in the nuclei of most of the post-embryonic blast cells. Intense nuclear staining was observed in the hypodermal blast cells H1, H2, V1-V6 and T and in all of the intestinal (E) cells and weaker staining was observed in both neuroblasts Q1 and Q2, in the mesoblast M cell and in P cells (P1/2, P3/4 and P5/6). During L1, staining is seen in the progeny of the hypodermal blast cells H1, H2 V1-V6 and T and in all of the intestinal (E) cells. Staining in P-cell nuclei fades before migration into the ventral nerve cord but reappears later in some of their progeny cells. The embryo-derived nuclei in the hypodermal syncytial cell
hyp7, ABarpppapa, ABplaapppp, Cpaaaa, Cpaapa, Cpaapp, Cpapaa, all stain for the
lin-14 protein during the L1 stage. Terminally differentiated nuclei from embryonic body muscle also accumulate the
lin-14 protein. Nuclei of many but not all neuronal cells stain with the antibody (e.g. BDU, ALM, CAN but not HSN). All of the embryonically generated ventral cord neurons and some but not all of the neurons of the nerve ring and the posterior ganglion accumulate the
lin-14 protein in their nuclei during the L1 stage. Late L1 stage, staining is seen in all nuclei except in the neuronal nuclei staining is much weaker. In addition, more neurons of the nerve ring and posterior ganglion stain than at the earlier stages. Thus, in the hypodermal and intestinal cell lineages,
lin-14 protein level peaks during early L1 and fade entirely by L2. In the many neuronal cells,
lin-14 protein peak during mid to late L1 and fade by L2. Pn.p accumulates
lin-14 protein at the L3 stage, although, very weak staining is seen before the Pn.p cells divide. This staining fades by early L4, In occasional L2 and L3 stage animals, weak staining is observed in nuclei and cytoplasm of hypodermal, neuronal and intestinal cells. Patches of staining in hypodermal or intestinal nuclei is only rarely observed in very old adults. In most adults, staining reappears only in the mature oocyte nuclei of hermaphrodites at meiotic prophase I when the chromosomes are condensed. The oocyte nuclear staining disappears after fertilization. Quantitation of immunoblots show that the level of
lin-14 protein relative to a pharyngeal myosin control decreases >= 25-fold from L1 to L2.