Discovery and characterization of endometrial epithelial messenger ribonucleic acids using the ovine uterine gland knockout model

Prolonged exposure of the developing neonatal ovine uterus to a progestin f rom birth prevents uterine gland development and creates an adult endometri al phenotype characterized by the absence of glandular epithelium, the uter ine gland knockout (UGKO) phenotype. This study used endometrium from norma l and UGKO sheep to identify messenger RNAs (mRNAs) expressed differentiall y in the endometrial epithelium using the molecular techniques of mRNA diff erential display PCR (DD-PCR) and suppression subtractive complementary DNA (cDNA) hybridization (SSH). Sequence analyses of DD- and SSH-identified an d cloned cDNAs indicated similarity of some to known mRNAs, including p-lac toglobulin, alkaline phosphatase, type B and D endogenous sheep retroviruse s, gp330/megalin, matrix Gla protein, and others. Other cDNAs were not simi lar to any known sequences and are considered novel, although some of these match human expressed sequence tags. In situ hybridization analyses of ute ri from cyclic and pregnant ewes indicated that all DD-PCR- and SSH-identif ied mRNAs were expressed in either the endometrial lumenal and/or glandular epithelium, although some were also expressed in other uterine cell types. Northern and in situ hybridization analyses revealed that patterns of mRNA expression for most clones were affected by the day of the estrous cycle a nd pregnancy in a manner consistent with regulation by progesterone. Studie s demonstrate the utility of the ovine UGKO model as a tool with which to i dentify known and novel uterine epithelial-specific genes. Cloned cDNAs ide ntified here are expressed sequence tags useful for comparative and physica l genetic mapping and may be used to reveal new factors and pathways regula ting endometrial function.