We have previously isolated deletion mutants for a set of genes, that possibly have germline-related functions. Here we report partial characterization of three such genes. One of them encodes a ubiquitin C-terminal hydrolase and the other two encode RNP-type RNA-binding proteins. The
rnp-1 gene encodes a possible homolog of Drosophila RNA-binding protein LARK. LARK has two RNA recognition motifs and a retroviral-type zinc finger. It is required both maternally and zygotically for development, and seems to be involved in circadian clock output pathway. The gonad of
rnp-1(RNAi) worms contained a reduced number of germ cells, with abnormal oocytes. The
rnp-1 deletion mutant we isolated was more severely sterile than the RNAi worms, with gonadal arms being distorted and oocytes missing. The F30A10.10 gene encodes a protein with conserved active centers for ubiquitin C-terminal hydrolase, but apparently with no homologs in other species. Disruption of F30A10.10 resulted in the formation of an abnormal gonad, which contained neither sperm nor oocytes but showed vacuolous germ cells in the proximal region. The third gene, Y73B6BL.6, encodes an hnRNP, which is homologous to Drosophila Squid (Sqd) protein and C. tentans
hrp36. Sqd/hrp36 has two RNA recognition motifs and an M9-like sequence. Sqd is required for the correct localization of several mRNAs in Drosophila oocytes, and
hrp36 behaves as a shuttling protein which accompanies mRNA from the nucleus to polysomes in the cytoplasm. RNAi against Y73B6BL.6 caused a sterile phenotype that is similar to but not exactly the same as F30A10.10 RNAi. A Y73B6BL.6 deletion mutant showed essentially the same phenotypes as in the case of RNAi, namely vacuolous germ cells and reduced progeny size.