Assessment of X chromosome dosage compensation in Caenorhabditis elegans by phenotypic analysis of lin-14.
Caenorhabditis elegans compensates for the difference in X chromosome gene dose between males (XO) and hermaphrodites (XX) through a mechanism that equalizes the levels of X-specific mRNA transcripts between the two sexes. We have devised a sensitive and quantitative genetic assay to measure perturbations in X chromosome gene expression caused by mutations that affect this process of dosage compensation. The assay is based on quantitating the precocious alae phenotype caused by a mutation that reduces but does not eliminate the function of the X-linked gene lin-14. We demonstrate that in diploid animals the lin-14 gene is dosage compensated, implying that the normal dosage compensation mechanism in C. elegans lacks the capacity to compensate completely for the additional X chromosome in triplo-X animals. Using the lin-14 assay we compare the effects of mutations in the genes dpy-21, dpy-26, dpy-27, dpy-28, and dpy-22 on X-linked gene expression. Additionally, in the case of dpy-21 we correlate the change in phenotypic expression of lin-14 with a corresponding change in the lin-14 mRNA transcript level.
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
L
L
DeLong
L P
LP
Casson
B J
BJ
Meyer
D000818:Animals; D002107:Caenorhabditis / Q000235:genetics*; D012734:Disorders of Sex Development; D005260:Female; D008297:Male; D009154:Mutation; D010641:Phenotype; D014960:X Chromosome