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RNA PROFILES OF EJACULATED HUMAN SPERMATOZOA
Citation:
Thompson, K E., W Bao, S P. Darney, H Ren, J C. Rockett, J E. Schmid, L F. Strader, AND D J. Dix. RNA PROFILES OF EJACULATED HUMAN SPERMATOZOA. Presented at Society for the Study of Reproduction, Vancouver, British Columbia, Canada, August 1-4, 2004.
Description:
RNA Profiles of Ejaculated Human Spermatozoa
Kary E. Thompson, Wenjun Bao, Sally D. Perreault, Hongzu Ren, John C. Rockett, Judith E. Schmid, Lillian F. Strader, David J. Dix
Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
Mature spermatozoa are transcriptionally inactive, but have been shown to contain residual mRNAs expressed earlier in germ cell development. This study was designed to profile the normal RNA content of ejaculated spermatozoa from fertile men and characterize individual variability. Seventeen healthy subjects (age 18-40) of self-reported fertility were recruited for the study. Semen was collected and subjected to routine analysis. Sperm were washed twice (0.75% Triton-X, 0.1% SDS) to lyse any somatic cells. RNA was then isolated from the sperm and confirmed to be free of gDNA. Agilent bioanalyzer analysis demonstrated the RNA to be free of 18S/28S rRNA and enriched with mRNA. RNA was then amplified twice and labeled with biotin-labeled nucleotides before hybridization to Affymetrix U133+2.0 arrays (54,120 probe sets; 38,572 unique Unigene IDs). On average, the RNA samples hybridized to 15,997 ? 616 probes (30% present). Based on these results, mature spermatozoa from fertile men would be expected to hybridize to 14,691-17,303 probes with 95% confidence. Genes with the highest mean intensity (greatest abundance) included numerous spermatogenic genes (e.g., transition protein 1, testis specific protein 1, protamine 1, outer dense fiber of sperm tails 1), and many others which have been previously identified in ejaculated human spermatozoa. When examined for consistent expression across all 17 subjects, 4,968 probes representing 3,816 unique UniGene IDs were hybridized by every sample. When this analysis is expanded to include probes identified in all but one of the subjects, 7,027 probes representing 5,227 unique UniGene IDs were hybridized by 16 of 17 samples. Therefore, 31% of the expressed probes were hybridized by all samples and 44% of expressed probes were hybridized by all but one sample. This suggests that there is a core set of approximately 5,000 genes expressed across individuals, in addition to a certain degree of individual variability. Thus, human sperm contain a common set of RNAs reflective of spermatogenesis and male fertility, with variation in gene expression suggesting the utility of sperm RNA as a potential biomarker for reproductive exposures. This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.