title: The gap junctional protein INX-14 functions in oocyte precursors to promote C. elegans sperm guidance.
abstract: Innexins are the subunits of invertebrate gap junctions. Here we show that the innexin INX-14 promotes sperm guidance to the fertilization site in the Caenorhabditis elegans hermaphrodite reproductive tract. inx-14 loss causes cell nonautonomous defects in sperm migration velocity and directional velocity. Results from genetic and immunocytochemical analyses provide strong evidence that INX-14 acts in transcriptionally active oocyte precursors in the distal gonad, not in transcriptionally inactive oocytes that synthesize prostaglandin sperm-attracting cues. Somatic gonadal sheath cell interaction is necessary for INX-14 function, likely via INX-8 and INX-9 expressed in sheath cells. However, electron microscopy has not identified gap junctions in oocyte precursors, suggesting that INX-14 acts in a channel-independent manner or INX-14 channels are difficult to document. INX-14 promotes prostaglandin signaling to sperm at a step after F-series prostaglandin synthesis in oocytes. Taken together, our results support the model that INX-14 functions in a somatic gonad/germ cell signaling mechanism essential for sperm function. We propose that this mechanism regulates the transcription of a factor(s) that modulates prostaglandin metabolism, transport, or activity in the reproductive tract.
authors: Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors: Johnathan W
authors: JW
authors: Edmonds
authors: Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors: Shauna L
authors: SL
authors: McKinney
authors: Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
authors: Jeevan K
authors: JK
authors: Prasain
authors: Department of Cell Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA. Electronic address: mamiller@uab.edu.
authors: Michael A
authors: MA
authors: Miller
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000502:physiology*; D002853:Chromatography, Liquid; D005227:Fatty Acids / Q000008:administration & dosage; D005260:Female; D017629:Gap Junctions / Q000378:metabolism*; D008297:Male; D008845:Microinjections; D011453:Prostaglandins / Q000378:metabolism; D034622:RNA Interference; D015398:Signal Transduction; D021241:Spectrometry, Mass, Electrospray Ionization; D013094:Spermatozoa / Q000166:cytology*; D053719:Tandem Mass Spectrometry; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029742:Caenorhabditis elegans Proteins; D005227:Fatty Acids; D011453:Prostaglandins; D014157:Transcription Factors