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. 2012 Mar 15;8(3):e1002553. doi: 10.1371/journal.pgen.1002553

Figure 1. qm179 is allelic to tat-2, which encodes a protein homologous to mammalian ATP8B1.

Figure 1

(A) Both the qm179 and tat-2(tm1634) deletion mutation show a short defecation cycle in the wild type background and suppress the slow defecation of clk-1(qm30) mutants in double mutant combinations. Furthermore the tat-2(tm1634) deletion mutations fails to complement qm179 in both the wild type and clk-1 backgrounds. The bars represent the mean defecation cycle of animals that have been scored for three consecutive defecation cycles each in the case of clk-1(qm30) mutants and for five consecutive defecation cycles for all other genotypes. The error bars represent S.E.M. (n≥20 animals for each genotype). The asterisks indicate that the data are significantly different from that of wild-type or clk-1 mutants. All differences were significant at P<0.0001 by a t-test. (B) Schematic representation of the tat-2 coding region and the lesions of the two alleles. TAT-2 is a membrane protein with 8 predicted transmembrane domains (red) and several consensus domains for all classes of P-type ATPases (blue) or specific for the P4 P-type ATPase (green). One of the P4 P-type ATPase-specific consensus domains harbors the residue that is changed in the qm179 allele (alanine 665 to threonine). This residue (indicated by an asterisk) is absolutely conserved among mammalian ATP8B1, C. elegans TAT-1, and yeast DRS2. Residues that are not perfectly conserved in this region are underlined. (C) The suppression of clk-1 produced by the tat-2(qm179) mutation can be partially rescued by transgenic expression of a cDNA coding for the mouse homologue ATP8B1 under the control of the endogenous tat-2 promoter (Ptat-2::mAtp8b1). Treating clk-1(qm30); tat-2(qm179) mutants that harbor the Ptat-2:mAtp8b1 construct with RNAi against mAtp8b1 abolished the rescue but had no effect by itself. The bars represent the mean defecation cycle of animals that have been scored for five consecutive defecation cycles. The error bars represent S.E.M. (n≥20 animals for each genotype). Differences were tested by a t-test; * represents P<0.05.