AN INCREASE IN EXPRESSION OF THE LIPOCALIN 24P3 IS FOUND IN MOUSE UTERUS COINCIDENT WITH BIRTH

OBJECTIVE: To provide novel insights into the molecular events associa ted with parturition, a differential screen was made of a mouse uterin e complementary deoxyribonucleic acid library to identify selectively expressed genes in late pregnancy. STUDY DESIGN: A differential hybrid ization was used to screen a mouse complementary deoxyribonucleic acid library prepared from late pregnancy uterus. A 1 kb clone was isolate d that was subsequently identified as 24p3, a member of the lipocalin family. By use of radiolabeled complementary deoxyribonucleic acid pro bes prepared from this clone Northern hybridizations were conducted ag ainst total ribonucleic acid purified from mouse uterus collected duri ng late pregnancy and the first week after birth and a variety of othe r mouse tissues to determine whether this gene is selectively expresse d in the uterus coincident with parturition. RESULTS: Low levels of me ssage for the 24p3 gene could be detected in uterine ribonucleic acid, but there was a massive increase in the level of message for this gen e on the days surrounding birth. Northern hybridizations conducted aga inst additional tissues collected from both pregnant and nonpregnant m ice did not detect message to a similar degree as found in the uterus. CONCLUSIONS: The uterus constitutes a major site of expression of thi s gene, particularly near birth. The expression of this gene coinciden t with birth suggests a potential physiologic role of the neutrophil w ith the induction of labor.