Inositol 1,4,5-Trisphosphate Signaling Regulates Mating Behavior inCaenorhabditis elegansMales

Abstract

Complex behavior requires the coordinated action of the nervous system and nonneuronal targets. Male mating in Caenorhabditis elegans consists of a series of defined behavioral steps that lead to the physiological outcomes required for successful impregnation. We demonstrate that signaling mediated by inositol 1,4,5-trisphosphate (IP 3 ) is required at several points during mating. Disruption of IP 3 receptor (itr-1) function results in dramatic loss of male fertility, due to defects in turning behavior (during vulva location), spicule insertion and sperm transfer. To elucidate the signaling pathways responsible, we knocked down the six C. elegans genes encoding phospholipase C (PLC) family members. egl-8, which encodes PLC-␤, functions in spicule insertion and sperm transfer. itr-1 and egl-8 are widely expressed in the male reproductive system. An itr-1 gain-of-function mutation rescues infertility caused by egl-8 RNA interference, indicating that egl-8 and itr-1 function together as central components of the signaling events controlling sperm transfer.

ANK Repeat-Domain of SHN-1 Is Indispensable for In Vivo SHN-1 Function in C. elegans

“…The defect in male fertility of shn-1(tm488) mutant was comparable to that of itr-1(sa73)(lf) mutant. As previously described, the itr-1(sa73)(lf) mutant showed a severe male fertility defect (Gower et al, 2005). Taken together, these results suggest that shn-1 is essential for both hermaphrodite and male fertility in C. elegans.…”

“…Male mating behaviors are composed of a series of steps: hermaphrodite recognition, backing, turning, vulval location and copulation. We specifically examined the male turning behavior of shn-1 males since it has been described that itr-1 plays important roles in mating especially in male turning behavior (Gower et al, 2005). Similarly most of our studies also show the genetic relation of itr-1 and shn-1.…”

“…The percentage of self-progeny versus crossed progeny produced from each individual was determined. Male mating behavior (Gower et al, 2005) was assayed by placing a single young adult male on a mating plate containing 20 young adults of unc-13(e1091) hermaphrodites. To score turning ability, turns were scored in the 3 min observation period for each male.…”

FMRFamide-Like Neuropeptides and Mechanosensory Touch Receptor Neurons Regulate Male Sexual Turning Behavior inCaenorhabditis elegans

“…MAB-23 is a DM domain transcription factor necessary for the differentiation of sexspecific tissues, and mab-23 males are unable to adopt the appropriate turning posture because of a diagonal muscle differentiation defect (Lints and Emmons, 2002). The IP 3 receptor gene itr-1 is expressed in CP8/9, and diagonal muscles and itr-1 mutant males also exhibit the wide-turn and late-turn phenotypes (Gower et al, 2005). Hence, the "ray sensorimotor circuit" is one element required for copulatory turning (Fig.…”

Mos1Mutagenesis Reveals a Diversity of Mechanisms Affecting Response ofCaenorhabditis elegansto the Bacterial PathogenMicrobacterium nematophilum

“…Although EGL-8 is expressed in most of the neurons of the worm, it is also expressed in the posterior intestine (Lackner et al 1999;Miller et al 1999). Recent studies have also indicated that EGL-8 functions in pharyngeal pumping, sperm transfer, and Ca 21 oscillation-associated posterior body contractions of the intestine, suggesting that it may function in nonneuronal tissues (Bastiani et al 2003;Steger and Avery 2004;Espelt et al 2005;Gower et al 2005). Whether or not EGL-8 feeds into the ERK/MAP kinase cascade or acts in a parallel pathway remains to be determined.…”