Chakravarti S, Hassell J R, Phillips S L
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pennsylvania.
Dev Dyn. 1993 Jun;197(2):107-14. doi: 10.1002/aja.1001970204.
F9 embryonal cells can be induced to differentiate and synthesize basement membrane proteins. Perlecan and laminin are two basement membrane constituents that have extensive regions of homology. Expression of perlecan and laminin B1 genes was followed during differentiation of F9 cells by measurements of transcription rate and mRNA abundance using nuclear run on assays and Northern hybridizations, respectively. The rate of precursor protein synthesis was determined by immunoprecipitation from lysates of pulse-labeled F9 cells. The results showed that perlecan gene expression responds more rapidly after induction than does laminin B1 gene expression but is ultimately expressed at a substantially lower level than laminin. Thus, the perlecan and laminin genes appear to be regulated by different mechanisms and their gene products are not made in stoichiometric amounts.
F9胚胎细胞可被诱导分化并合成基底膜蛋白。基底膜聚糖和层粘连蛋白是两种具有广泛同源区域的基底膜成分。在F9细胞分化过程中，分别使用核转录分析和Northern杂交技术，通过测量转录速率和mRNA丰度来跟踪基底膜聚糖和层粘连蛋白B1基因的表达。通过对脉冲标记的F9细胞裂解物进行免疫沉淀来测定前体蛋白的合成速率。结果表明，基底膜聚糖基因表达在诱导后比层粘连蛋白B1基因表达反应更快，但最终表达水平远低于层粘连蛋白。因此，基底膜聚糖和层粘连蛋白基因似乎受不同机制调控，且它们的基因产物并非按化学计量产生。
