Figure 2. UNC-34 localizes to the leading edge of cell protrusions and to apical junctions.(A and A') Confocal projections of dorsolateral (A) and ventrolateral (A') surfaces (anterior is to the left) of the same embryo stained at mid-enclosure with anti-UNC-34 show broad expression throughout the embryo with enrichment at apical epidermal junctions.(B-E) Time-lapse sequence of projected confocal Z series, visualizing UNC-34::GFP in the ventral leading cell region (anterior is to the left) during enclosure. Besides apical junction enrichment, UNC-34::GFP is also present at the leading edge (arrowheads) of leading cell protrusions (C). Junctions enriched in UNC-34::GFP become apparent along the anterior and posterior borders of migrating cells ([C], arrow). Protrusions in contralateral partners meet at the ventral midline ([D], arrow), where apical junctions enriched with UNC-34::GFP eventually form ([E], arrow).(F-H) Confocal images of a wild-type 3-fold stage embryo expressing UNC-34::GFP (F) costained for AJM-1 (G). A merged image is shown in (H).(I-K) Representative wide-field images of wild-type (I),
ajm-1(
ok160) (J), and
hmr-1(
zu389) maternal and zygotic loss (K) embryos expressing UNC-34::GFP. UNC-34::GFP at apical junctions is misdistributed into puncta in
ajm-1 embryos ([J], arrowheads) but is largely normal in
hmr-1 embryos.(L-O) Immunostaining of UNC-34 in embryos carrying a truncated
ajm-1::gfp transgene lacking a putative consensus binding site for Ena/VASP proteins (
ajm-1(102-868)::gfp). (L) and (M) show a wild-type embryo expressing AJM-1(102-868)::GFP. UNC-34 localizes to junctions ([M], arrow). UNC-34 is also prominently expressed in neurons of the nerve ring (asterisk). (N) and (O) show an
ajm-1(
ok160) embryo rescued by
ajm-1(102-868)::gfp. Although the truncated AJM-1 localizes to junctions (N), it is insufficient to localize UNC-34 there (O), despite robust expression in neurons (asterisk).Scale bars represent 10 um.