PARENT SESSION
GENE REGULATION AND FUNCTION IN THE REPRODUCTIVE AXIS
Kent
7:30 AM-10:00 AM

(360) MX, ESTROGEN RECEPTOR (ER), AND PROGESTERONE RECEPTOR (PR) EXPRESSION IN OVINE PLACENTOMAL AND INTERPLACENTOMAL ENDOMETRIUM DURING DAYS 25 TO 120 OF PREGNANCY.

Sinor, Stacy¹, Joyce, Margaret¹, Yankey, Stephanie¹, Assiri, Abdullah¹, Kodali, Kiran¹, Hartt, Leslie¹, Robison, Matthew¹, Johnson, Greg¹, Ott, Troy¹, ¹ Dept of Animal and Veterinary Science, Moscow, ID

ABSTRACT- Mx is an interferon-tau (IFNt) stimulated gene up-regulated during diestrus and early pregnancy in ovine endometrium. While the antiviral function of Mx is well-characterized, functions for Mx during the cycle or pregnancy in the endometrium have not been described. We hypothesize that Mx is involved in pregnancy establishment and maintenance and is co-regulated by steroids and IFNt. To examine Mx, ER and PR expression during pregnancy, placentomal (PE) and interplacentomal endometrium (IPE) was collected from ewes on Day (D) 25, 30, 35, 40, 45, 50, 55, 60, 80, 100 and 120 of pregnancy (n=4 /day). Total cellular RNA and fixed uterine sections were analyzed by slot-blot and in situ hybridization. Mx mRNA levels were highest on D25, decreased substantially by D30 and remained constant to D60, then decreased again at D80 and remained low through D120 (P<0.01). On D25, Mx mRNA was localized to the luminal epithelium (LE), stratum compactum stroma (scST) and shallow glandular epithelium (sGE) of IPE. Expression was patchy from D30-45 in scST and LE and remained patchy in the LE at the fetal-maternal interface from D55-120. In PE, maternal ST exhibited patchy Mx mRNA expression from D40-50. Similar to Mx, PR mRNA levels were highest on D25-30, decreased considerably by D35 and remained constant to D55, then decreased again by D60 and remained low through D120 (P<0.01). While PR mRNA was localized across the uterine wall in IPE, it was strongest in the scST from D25-45 and at the fetal-maternal interface through D80, and then declined in all regions through D120. PR was also expressed in the maternal ST of PE from D40-55. ER mRNA levels were highest from D25-40, decreased at D40 and remained constant through D80, then declined through D120 (P<0.01). In IPE, ER mRNA was expressed across the uterus during early gestation then localized primarily to the scST from D30-120. Maternal ST of PE showed strong ER hybridization, which became patchy from D80-120. Results show that Mx expression continues throughout ovine gestation, particularly at the fetal-maternal interface, suggesting Mx may have a function after pregnancy establishment. Further, similar spatial and quantitative patterns of Mx and PR mRNA indicate a possible role for steroids in the regulation of Mx in the ovine endometrium during gestation. USDA NRI grant #00-35203-9185 to TLO.

KEY WORDS: sheep, uterus, Mx, steroid receptors