The C. elegans sex determination gene laf-1 encodes a putative DEAD-box RNA helicase.
The Caenorhabditis elegans gene laf-1 is critical for both embryonic development and sex determination. Laf-1 is thought to promote male cell fates by negatively regulating expression of tra-2 in both hermaphrodites and males. We cloned laf-1 and established that it encodes a putative DEAD-box RNA helicase related to Saccharomycescerevisiae Ded1p and Drosophila Vasa. Three sequenced laf-1 mutations are missense alleles affecting a small region of the protein in or near helicase motif III. We demonstrate that the phenotypes resulting from laf-1 mutations are due to loss or reduction of laf-1 function, and that both laf-1 and a related helicase vbh-1 function in germline sex determination. Laf-1 mRNA is expressed in both males and hermaphrodites and in both the germline and soma of hermaphrodites. It is expressed at all developmental stages and is most abundant in embryos. LAF-1 is predominantly, if not exclusively, cytoplasmic and colocalizes with PGL-1 in P granules of germline precursor cells. Previous results suggest that laf-1 functions to negatively regulate expression of the sex determination protein TRA-2, and we find that the abundance of TRA-2 is modestly elevated in laf-1/+ females. We discuss potential functions of LAF-1 as a helicase and its roles in sex determination.
Department of Genetics, University of Wisconsin, 425-G Henry Mall, Madison, WI 53706, USA.
Amy
A
Hubert
Philip
P
Anderson
D000595:Amino Acid Sequence; D000818:Animals; D015152:Blotting, Northern; D017173:Caenorhabditis elegans / Q000196:embryology / Q000235:genetics*; D053487:DEAD-box RNA Helicases / Q000737:chemistry / Q000235:genetics*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010802:Phylogeny; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D019849:Sex Determination Processes; D019076:Transgenes
D053487:DEAD-box RNA Helicases