Abstract
BackgroundIn the hermaphrodite of the nematode Caenorhabditis elegans, the first germ cells differentiate as sperm. Later the germ line switches to the production of oocytes. This process requires the activity of a genetic regulatory network that includes among others the fem, fog and mog genes. The function of some of these genes is germline specific while others also act in somatic tissues. DEAD box proteins have been shown to be involved in the control of gene expression at different steps such as transcription and pre-mRNA processing.ResultsWe show that the Caenorhabditis elegans gene mel-46 (maternal effect lethal) encodes a DEAD box protein that is related to the mammalian DDX20/Gemin3/DP103 genes. mel-46 is expressed throughout development and mutations in mel-46 display defects at multiple developmental stages. Here we focus on the role of mel-46 in the hermaphrodite germ line. mel-46(yt5) mutant hermaphrodites are partially penetrant sterile and fully penetrant maternal effect lethal. The germ line of mutants shows variable defects in oogenesis. Further, mel-46(yt5) suppresses the complete feminization caused by mutations in fog-2 and fem-3, two genes that are at the top and the center, respectively, of the genetic germline sex determining cascade, but not fog-1 that is at the bottom of this cascade.ConclusionThe C. elegans gene mel-46 encodes a DEAD box protein that is required maternally for early embryogenesis and zygotically for postembryonic development. In the germ line, it is required for proper oogenesis. Although it interacts genetically with genes of the germline sex determination machinery its primary function appears to be in oocyte differentiation rather than sex determination.
Highlights
In the hermaphrodite of the nematode Caenorhabditis elegans, the first germ cells differentiate as sperm
In spite of the caveat that the mutant alleles used in our analyses are not null, altogether, our results suggest that mel-46(yt5) masculinizes the germ line and acts downstream of or in parallel with fem-3 and fog-2 and our results are consistent with a role of mel-46 upstream of fog-1
We report the genetic isolation, cloning and molecular and phenotypic characterization of the C. elegans gene mel-46. This gene encodes a putative DEAD box helicase and is required at least three times during development, namely: i) maternally for embryogenesis; ii) zygotically for progression through larval development and iii) in the hermaphrodite germ line. Consistent with these observations, we found the MEL-46 protein to be present at all developmental stages and in the germ line and in the soma
Summary
In the hermaphrodite of the nematode Caenorhabditis elegans, the first germ cells differentiate as sperm. Later the germ line switches to the production of oocytes. This process requires the activity of a genetic regulatory network that includes among others the fem, fog and mog genes. DEAD box proteins have been shown to be involved in the control of gene expression at different steps such as transcription and pre-mRNA processing. The nematode Caenorhabditis elegans has two sexes, a selffertile hermaphrodite and a male [1]. Hermaphrodites are somatically female and undergo a transient period of spermatogenesis during the L4 larval stage. The production of mature germ cells involves a switch from mitosis to meiosis and (page number not for citation purposes)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
