PARENT SESSION

(T719) GENE EXPRESSION PROFILES IN MOUSE EARLY-DIFFERENTIATED WHOLE FETAL GONADS AND ISOLATED SOMATIC SUPPORT CELLS.

Bouma, Gerrit ¹, Affourtit, Jason ¹, Washburn, Linda ¹, Bult, Carol¹, Eicher, Eva¹, ¹ The Jackson Laboratory, Bar Harbor, ME

ABSTRACT- Microarray analysis is a powerful tool for simultaneously examining expression levels for thousands of genes. Recent advances in linear RNA amplification techniques allow gene expression patterns to be analyzed in specific cell populations without loss of representation of the original transcript population. To obtain a better understanding of the genetic factors involved in fetal gonad differentiation, we conducted GeneChip microarray analysis to examine gene expression differences between XX and XY fetal gonads. The Mouse Genome 430 2.0 array was chosen because it provides the most extensive coverage of the transcribed mouse genome using the Affymetrix platform. Differences in gene expression were identified at embryonic day (E) 12.5 and E13 in XX and XY whole C57BL/6JEi mouse gonads, and isolated E13 XX and XY somatic support cells (SSC) (i.e., granulosa cells in XX and Sertoli cells in XY gonads). At E12.5, when XX and XY fetal gonads are visually distinguishable, we identified 1814 genes that are significantly differentially expressed. At E13, when germ cells enter meiotic prophase in XX gonads and arrest in mitotic G1 in XY gonads, 456 significantly differentially expressed genes were identified. For E13 XX and XY SSCs, 708 genes were significantly differentially expressed. Interestingly, a larger number of differentially expressed genes was found between E12.5 and E13 XX gonads compared to the number of differentially expressed genes between E12.5 and E13 XY gonads, confirming that fetal ovarian development is a dynamic developmental process at this stage. Genome distribution analysis was conducted to identify genomic regions containing an over-abundance of significantly differentially expressed genes. The data obtained from these experiments will form the basis for hypotheses regarding the function of newly reported genes expressed in fetal gonad development and differentiation.

KEY WORDS: transcriptome, gonad development