Risek B, Guthrie S, Kumar N, Gilula N B
Department of Molecular Biology, Research Institute of Scripps Clinic, La Jolla, California 92037.
J Cell Biol. 1990 Feb;110(2):269-82. doi: 10.1083/jcb.110.2.269.
The expression of three different gap junction transcripts, alpha 1 (Cx43), beta 1 (Cx32), and beta 2 (Cx26) was examined in several organs during pregnancy in the rat. In all of the organs that were examined--uterus, ovary, heart, and liver--there was a strong correlation between levels of gap junction mRNA and gap junction antigens that were detected at different stages of pregnancy. A striking change in alpha 1 transcript levels (a 5.5-fold increase) was detected in the uterine myometrium on the day before parturition. This elevation of the alpha 1 transcript is thought to be associated with the formation of gap junctions that are required for synchronizing the contractility of the myometrial cells during parturition. 2 d before parturition, there was a detectable elevation of beta 2 transcripts and protein in the endometrial epithelium, which was then followed by a dramatic decrease in beta 2 gap junctional protein on the day before parturition. There was also a substantial elevation of alpha 1 transcripts (a 6.7-fold increase) in the stromal regions of the ovary on the day before parturition that was identical to the temporal pattern of alpha 1 expression in the myometrium. In all three instances--the alpha 1 transcripts in the myometrium, beta 2 transcripts in the endometrium, and alpha 1 transcripts in the ovary--the transcript modulation appeared to be cell specific, because the changes in transcript levels of these three gene products occurred independently of the poly(A) + RNA concentrations at the same pregnancy stages in the respective organs. There were no specific changes detected in gap junction transcript levels in the heart and liver during pregnancy. These observations indicate that a cell-specific modulation of gap junction expression occurs in two regions of the uterus and the ovary during pregnancy. Further, it appears that the same gap junction gene in different organs, such as the alpha 1 gene in the uterine myometrium and the heart, can be differentially regulated.
在大鼠孕期的几个器官中检测了三种不同缝隙连接转录本α1（Cx43）、β1（Cx32）和β2（Cx26）的表达。在所有检测的器官——子宫、卵巢、心脏和肝脏——中，缝隙连接mRNA水平与在孕期不同阶段检测到的缝隙连接抗原之间存在很强的相关性。在分娩前一天，子宫肌层中检测到α1转录本水平有显著变化（增加了5.5倍）。α1转录本的这种升高被认为与分娩期间使子宫肌层细胞收缩同步所需的缝隙连接的形成有关。在分娩前2天，子宫内膜上皮中β2转录本和蛋白有可检测到的升高，随后在分娩前一天β2缝隙连接蛋白急剧下降。在分娩前一天，卵巢基质区域的α1转录本也有大幅升高（增加了6.7倍），这与子宫肌层中α1表达的时间模式相同。在所有这三种情况——子宫肌层中的α1转录本、子宫内膜中的β2转录本和卵巢中的α1转录本——中，转录本调节似乎是细胞特异性的，因为这三种基因产物的转录本水平变化在各自器官的相同孕期阶段独立于多聚腺苷酸+RNA浓度而发生。孕期心脏和肝脏中的缝隙连接转录本水平未检测到特异性变化。这些观察结果表明，孕期子宫和卵巢的两个区域会发生缝隙连接表达的细胞特异性调节。此外，不同器官中的相同缝隙连接基因，如子宫肌层和心脏中的α1基因，似乎可以受到不同的调节。
