CELF Family RNA–Binding Protein UNC-75 Regulates Two Sets of Mutually Exclusive Exons of the unc-32 Gene in Neuron-Specific Manners in Caenorhabditis elegans
Figure 1
The mutually exclusive exons of the unc-32 gene are regulated in tissue-specific manners.
(A) Schematic structure of the unc-32 gene. Numbered boxes indicate exons. The position of the 3′-splice site mutation in the unc-32 (e189) allele is indicated. Black triangles indicate positions and directions of the exonic primers used in the RT-PCR analyses shown in (B). (B) RT-PCR analyses of unc-32 exon 4 (left) and exon 7 (right) at the L1 and L4 larval stages. (C, D) Schematic illustration of the symmetric trio of the exon 4 reporter minigenes (C) and the symmetric pair of the exon 7 reporter minigenes (D) and the mRNA isoforms derived from them. The cDNA cassettes and the predicted ORFs for Venus/EGFP, mRFP and ECFP are colored in green, magenta and cyan, respectively. Green circles and red diamonds indicate the artificially-introduced initiation and termination codons, respectively. (E) Fluorescence images of an L4 larva of the exon 4 reporter worm ybIs1891 [eft-3::unc-32E4a-Venus eft-3::unc-32E4b-mRFP eft-3::unc-32E4c-ECFP]. E4a-Venus, E4b-mRFP and E4c-ECFP images in black-white and a merged image with pseudo colors. (F, G) Confocal images of the exon 7 reporter worms ybEx1440 [eft-3::unc-32E7-EGFP eft-3::unc-32E7b-mRFP]. (H) A fluorescence image of the unc-32 transcriptional fusion reporter worm ybEx1896 [unc-32::EGFP] containing 1.7-kb of the unc-32 promoter. int, intestine; N, neurons in head ganglia; phx, pharynx. Scale bars in (E), (F) and (H), 100 µm; in (G), 20 µm.