RNA helicase A (RHA) is a conserved protein with roles in transcription regulation and histone modification in a variety of organisms including flies and humans. In C. elegans, the null mutant
rha-1(
tm329) has a temperature-sensitive sterile phenotype in hermaphrodite and male worms (Walstrom et al. (2005) Mech. Dev. 122, 707). Others showed that
rha-1 is required for RNA interference in the germline (Robert et al. (2005) Genes Dev. 19, 782). We tested for interactions between
rha-1 and genes involved in two germline RNAi pathways. The first was the 26G RNAi pathway (Han et al. (2009) PNAS 106, 18674) that requires
eri-1 and
rrf-3, and the second was the 22G endo-siRNA pathway, downstream of the
prg-1-dependent 21U piRNA pathway, that requires
mut-7 and
rde-2 (Bagijn et al. (2012) Science 337, 574; Shirayama et al. (2012) Cell 150, 65). We found that
rha-1(
tm329);
eri-1(
mg366) mutant hermaphrodites produced significantly fewer offspring at 20 deg C than
rha-1 or
eri-1 hermaphrodites. In extensive real-time RT-PCR assays,
rha-1 hermaphrodites and males did not have significantly increased expression of 26G-regulated genes or 21U/22G-regulated transposons. However, the expression of 26G-regulated sperm-enriched genes in
rha-1;
eri-1 males was slightly reduced compared to
eri-1 males. We also found that
rha-1;
mut-7(
pk204) hermaphrodites produced fewer offspring at 20 deg C than
mut-7 or
rha-1 hermaphrodites because they made fewer sperm. Preliminary real-time RT-PCR with 21U/22G-regulated transposons showed that some transposons were overexpressed in
rde-2 or
mut-7 hermaphrodites as expected and that
rha-1;
rde-2(
ne221) and
rha-1;
mut-7 hermaphrodites often had expression levels restored to near wild-type levels. These results indicate that the germline defects in
rha-1(
tm329) worms are not due to major alterations in the expression of genes controlled by the 26G or 21U/22G RNAi pathways. However, RHA-1 appears to be required for the overexpression of some 21U/22G-regulated transposons in
rde-2 and
mut-7 worms.