Figure 3. KIN-20 Is the Closest C. elegans Homolog to Drosophila DOUBLETIME. (A) Phylogenetic tree of casein kinase I-predicted protein sequences from the following metazoans: Hs, Homo sapiens; Ma, Mesocricetus auratus; Ce, Caenorhabditis elegans; Dm, Drosophila melanogaster.(B) Schematic of
kin-20 isoforms. Solid bars represent translated sequences and hatched bars represent untraslated sequences.(C) mRNA expression profiles of
kin-20. A developmental Northern blot with total RNA from each developmental stage (E, embryos; L1-L4, larval stages 1-4; YA, young adult) was probed with a
kin-20 fragment. Three signals were detected at all developmental stages (
kin-20C at 4.0 kb,
kin-20A at 2.5 kb, and
kin-20B at 1.8 kb).(D) Schematic of the
kin-20::gfp translational fusion construct for
kin-20A and
kin-20C isoforms. The C-terminal GFP fusion consists of
kin-20-translated exons 3-7 under control of 3 kb of
kin-20 native promoter, and with the
unc-54 3'UTR.(E and F) KIN-20::GFP is expressed in seam cells and the hermaphrodite-specific neuron (HSN). (E) KIN-20::GFP localization to dividing seam cell pairs (indicated by small white arrowheads) in an L4-stage animal (magnification of 630). (F) KIN-20::GFP localization to the HSN (indicated by the large white arrowhead) in a late L4-stage animal (magnification of 1000). In (E) and (F), anterior is oriented toward the left, and dorsal is oriented toward the top.