Holewa B, Strandmann E P, Zapp D, Lorenz P, Ryffel G U
Universitätsklinikum Essen, Institut für Zellbiologie (Tumorforschung), Germany.
Mech Dev. 1996 Jan;54(1):45-57. doi: 10.1016/0925-4773(95)00460-2.
The tissue specific transcription factor HNF1 alpha (LFB1) expressed in liver, kidney, stomach and gut gets transcriptionally activated in Xenopus shortly after zygotic transcription starts. By microinjection into fertilized Xenopus eggs, a HNF1 alpha promoter fragment is activated in the middle part of developing larvae, reflecting the activation pattern of the endogenous HNF1 alpha gene. Mutational analysis of the HNF1 alpha promoter shows that HNF1 and HNF4 binding sites are essential for proper embryonic regulation. Since by injecting HNF4 mRNA into fertilized eggs the endogenous HNF1 alpha gene is activated ectopically and HNF4 is present as a maternal protein within an animal to vegetal gradient in the embryo, we assume that HNF4 initiates a transcriptional hierarchy involved in determination of different cell fates.
在肝脏、肾脏、胃和肠道中表达的组织特异性转录因子HNF1α（LFB1）在合子转录开始后不久就在非洲爪蟾中被转录激活。通过显微注射到受精的非洲爪蟾卵中，一个HNF1α启动子片段在发育中的幼虫中部被激活，这反映了内源性HNF1α基因的激活模式。对HNF1α启动子的突变分析表明，HNF1和HNF4结合位点对于正确的胚胎调控至关重要。由于通过将HNF4 mRNA注射到受精卵中，内源性HNF1α基因被异位激活，并且HNF4作为母体蛋白以动物到植物的梯度存在于胚胎中，我们推测HNF4启动了一个参与不同细胞命运决定的转录层次结构。
