549
ABDOMINAL-B HOXA-10 EXPRESSION IN NEONATAL AND ADULT PORCINE UTERINE TISSUES.
Bartol, Frank1, Campbell, Jennifer1, Tarleton, Becky1, Wiley, Anne1, Wower, Jacek1, 1
ABSTRACT- Abdominal-B Hoxa genes direct anteroposterior and radial patterning of Müllerian duct derivatives. Murine data indicate that Hoxa-10 expression is ultimately confined to the uterus. Hoxa-10 null mice display homeotic uterine transformations and general uterine hypoplasia. Uterine Hoxa-10 expression is steroid sensitive in adult mice and women. It is hypothesized that Hoxa-10 expression is a primary effector of uterine organization that may also be necessary to stabilize adult uterine structure and function. Because Hoxa-10 expression has not been investigated in the porcine uterus, objectives were to: (1) clone a partial cDNA for porcine Hoxa-10 using reverse transcription and the polymerase chain reaction (RT-PCR); (2) evaluate uterine Hoxa-10 expression between birth (postnatal day = PND 0) and PND 14, a critical period for porcine uterine development; and (3) evaluate adult endometrial Hoxa-10 expression and determine effects of pregnancy status on Hoxa-10 mRNA levels in cyclic (Cy) and pregnant (Px) gilts. Uteri were obtained by hysterectomy of neonatal gilts on PND 0, 7 and 14 (n=4/day), and adult gilts (n=12 Cy and 12 Px) on day 12 postestrus/mating (estrus = day 0). Total RNA was extracted from neonatal uterine and adult endometrial tissues. Using uterine RNA from PND 14, a 266 bp RT-PCR amplicon was generated, cloned, sequenced (GenBank AF281156) and found to be 96% homologous with human Hoxa-10. Expression of Hoxa-10 mRNA was evaluated in neonatal uterine tissue sections by in situ hybridization (ISH), and in adult endometrium by ribonuclease protection assay (RPA) using [35S] and [32P]UTP-labeled antisense cRNA probes generated from porcine Hoxa-10 cDNA template. Results of ISH showed uterine Hoxa-10 mRNA expression at birth that was primarily stromal, and increased thereafter such that signal was strongest in subepithelial stroma and myometrium by PND 14. Endometrial Hoxa-10 expression was detected by RPA in all adult gilts. Relative Hoxa-10 mRNA levels were 1.5-fold higher (P<.01) in Cy as compared to Px gilts. Data provide the first evidence of Hoxa-10 expression in neonatal and adult porcine uterine tissues, and that porcine uterine Hoxa-10 expression can reflect developmental, physiological and(or) endocrinological conditions. [USDA-NRI 98-3203-6198]
KEY WORDS: porcine uterus, homeobox genes, neonate, adult