Discipline: Biological Sciences
Diana Munguia - Alverno College
Co-Author(s): Allison Abbott , Department of Biological Sciences , Marquette University, Milwaukee, WI
Spermatogenesis is the production of mature spermatozoa and it is an essential for normal fertility. There are three types of small RNAs involved in spermatogenesis in a large number of organisms: microRNAs, endo-siRNAs and PIWI-interacting RNAs. It is unknown if microRNAs are required for spermatogenesis is the worm Caenorhabditis elegans. MicroRNAs work with Argonaute proteins as guide molecules to direct regulation of gene expression. To address whether MicroRNAs are involved in C. elegan spermatogenesis, we examined hermaphrodite C. elegans worms that contained mutations in the alg-2 and alg-5 Argonaute genes. The results of these mutant worms were compared to wild-type worms. Argonaute proteins act late in the microRNA biogenesis pathway and are associated with mature microRNAs. By studying these mutants, we can investigate whether ALG-5 acts with ALG-2 to regulate spermatogenesis and if microRNAs are involved in spermatogenesis in the worm. A defect in spermatogenesis will result in fewer functional sperm and a decrease in progeny as well as increased number of unfertilized oocytes. Two phenotypic analysis were conducted on the mutant and wild-type strains: a brood assay and a layoff assay. The brood assay is used to count the progeny the different strains produce while the layoff assay counts the number of embryos and oocytes a hermaphrodite can produce within a three-hour period. We found that the alg-2 and alg-5 mutations affect both the brood size and number of unfertilized oocytes compared to the wildtype worm. However, the alg-2 and alg-5 mutations did not demonstrate complete inhibition of spermatogenesis nor enhanced increase in unfertilized oocytes that has been observed with alg-3 and alg-4 mutations. From these results we can infer that the Argonaute proteins (alg-2 and alg-5) act to regulate spermatogenesis, likely working in the microRNA pathway. Additional assays will be performed to further test for a possible connection to the microRNA pathway.
Bertel, D. P. (2009, January 23). MicroRNA target recognition and regulatory functions.
Ghildiyal, M., & Zamore, P. D. (2009, February). Small silencing RNAs: an expanding universe.
Funder Acknowledgement(s): This Study was supported, in part, by a grant from the National Science Foundation (NSF Award DBI-1659595) awarded to Dr. Allison Abbott, Assistant Professor of Biology, Marquette University, Milwaukee, WI 53233. I also want to thank the Wisconsin Louis Stokes Alliance for Minority Participation (WiscAMP) for their support.
Faculty Advisor: Allison Abbott, email@example.com
Role: To address whether MicroRNAs are involved in C. elegan spermatogenesis, I was in charge of creating mutated strains that contained mutations in the alg-2 and alg-5 Argonaute genes. After creating the mutated strains, I created two phenotypic analysis that were conducted on the mutant and wild-type strains to count the progeny, embryos and oocytes of each strain.