2000 West Coast Worm Meeting abstract 33
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| 1 | Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305 |
| 2 | Department of Molecular and Cellular Biology, University of Arizona, Tuscon, AZ 85721 |
We have produced DNA microarrays containing genomic PCR products corresponding to 11,917 C. elegans genes. To identify genes expressed in the germ line, we compared wild-type gene expression levels to that of glp-4 mutants, in which the germ line precursor cells do not proliferate. We also compared a mutant strain making only sperm, fem-3(gf), to a mutant strain producing only oocytes, fem-1(lf), to identify both sperm-enriched and oocyte-enriched genes. Using a statistical criterion for significance, these experiments together define 1416 germ line-expressed genes that fall into three categories: 650 sperm-enriched, 258 oocyte-enriched, and 508 germ line-intrinsic. We have determined the temporal expression pattern of each of these genes during development. These germ line genes comprise a molecular definition of germ line components, and also provide the framework to identify individual genes involved in specific germ line functions. The sperm-enriched group contains an unusually large number of protein kinases and phosphatases. The oocyte-enriched group includes potentially new components of embryonic signaling pathways. The germ line-intrinsic group, defined as genes expressed similarly in germ lines making only sperm or only oocytes, contains a family of piwi-related genes that may be important for stem cell proliferation. Surprisingly, we found evidence for germ line-specific regulation of the X chromosome. Sperm-enriched and germ line-intrinsic genes are nearly absent from the X chromosome, and X-linked oocyte-enriched genes are expressed at about three fold lower levels than autosomal genes. Further, a marker for active gene expression (acetylated histone H4) is detectable on autosomes but staining is strongly reduced on the X chromosomes in germ line nuclei.