Identification of a novel leucine-rich repeat protein as a component of flagellar radial spoke in the Ascidian Ciona intestinalis.
Axonemes are highly organized microtubule-based structures conserved in many eukaryotes. In an attempt to study axonemes by a proteomics approach, we selectively cloned cDNAs of axonemal proteins by immunoscreening the testis cDNA library from the ascidian Ciona intestinalis by using an antiserum against whole axonemes. We report here a 37-kDa protein of which cDNA occurred most frequently among total positive clones. This protein, named LRR37, belongs to the class of SDS22+ leucine-rich repeat (LRR) family. LRR37 is different from the LRR outer arm dynein light chain reported in Chlamydomonas and sea urchin flagella, and thus represents a novel axonemal LRR protein. Immunoelectron microscopy by using a polyclonal antibody against LRR37 showed that it is localized on the tip of the radial spoke, most likely on the spoke head. The LRR37 protein in fact seems to form a complex together with radial spoke protein 3 in a KI extract of the axonemes. These results suggest that LRR37 is a component of the radial spoke head and is involved in the interaction with other radial spoke components or proteins in the central pair projection.
Padma
Potturi
P
Asamushi Marine Biological Station, Graduate School of Science, Tohoku University, Aomori 039-3501, Japan.
Satouh
Yuhkoh
Y
Wakabayashi
Ken-Ichi
K
Hozumi
Akiko
A
Ushimaru
Yuji
Y
Kamiya
Ritsu
R
Inaba
Kazuo
K
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics*; D002850:Chromatography, Gel; D002938:Ciona intestinalis; D018076:DNA, Complementary / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005407:Flagella / Q000378:metabolism*; D015723:Gene Library; D007150:Immunohistochemistry; D007930:Leucine / Q000737:chemistry*; D008297:Male; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism
D002352:Carrier Proteins; D018076:DNA, Complementary; D011993:Recombinant Fusion Proteins; D007930:Leucine