The T-box transcription factor SEA-1 is an autosomal element of the X:A signal that determines C. elegans sex.
Sex is determined in C. elegans by a chromosome-counting mechanism that tallies X chromosome dose relative to the sets of autosomes, the X:A ratio. A group of genes on X called X signal elements (XSEs) communicates X chromosome number by repressing the activity of the master sex-determination switch gene xol-1 in a dose-dependent manner. xol-1 is repressed by transcriptional and posttranscriptional mechanisms and is inactive in XX animals (hermaphrodite) but active in XO animals (male). Prior to our work, the nature of the autosomal signal and its target(s) were unknown. Here we show the signal includes discrete, trans-acting autosomal signal elements (ASEs) that counter XSEs to coordinately control both sex determination and dosage compensation. sea-1, the first autosomal signal element, encodes a T-box transcription factor that opposes XSEs by activating transcription of xol-1. Hence, xol-1 integrates both X and autosomal signals to determine sexual fate.
Powell
Jennifer R
JR
Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA.
Jow
Margaret M
MM
Meyer
Barbara J
BJ
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005799:Genes, Dominant / Q000235:genetics*; D005820:Genetic Testing; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D012730:Sex Chromosomes; D019849:Sex Determination Processes; D012744:Sex Ratio; D015398:Signal Transduction / Q000502:physiology; D020825:T-Box Domain Proteins / Q000235:genetics* / Q000378:metabolism; D015053:Zygote / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; C505146:SEA-1 protein, C elegans; D020825:T-Box Domain Proteins; C091429:XOL-1 protein, C elegans