Prchal J T, Papayannopoulou T, Yoon S H
Division of Hematology, University of Alabama, Birmingham 35294.
J Cell Physiol. 1990 Aug;144(2):287-94. doi: 10.1002/jcp.1041440215.
Spectrin is the major protein of the membrane erythrocyte skeleton. More recently, homologous but non-identical spectrins (fodrins) were also found in various non-erythroid tissues. Spectrin mRNA in erythroid and various non-erythroid cells was examined by direct hybridization with human alpha-spectrin, beta-spectrin (erythroid spectrins), and alpha-fodrin (non-erythroid spectrin) cDNA probes. Northern blot analysis of poly (A)+ RNA revealed a distinct pattern of expression in erythroid vs. non-erythroid cells. Erythroid cells from early erythroblasts to reticulocyte stage expressed two mRNA species of beta-spectrin, whereas they expressed only a single species of alpha-spectrin, and no alpha-fodrin mRNA. In contrast, non-erythroid cells (platelets, myeloid cells, liver, muscle, heart, cerebellum, and eye lens) expressed either no alpha-spectrin mRNA or a different molecular weight transcript(s) of this gene, and a single species of alpha-fodrin mRNA. Additionally, they also expressed from none to multiple species of beta-spectrin, and these were of different molecular size(s) from that found in erythroid cells (with the exception of platelets). Transcripts of non-erythroid spectrin, alpha-fodrin, were found as a single copy only in non-erythroid tissues. Human and murine erythroleukemia cells expressed both erythroid spectrin transcripts in addition to alpha-fodrin and raise the possibility that erythroid progenitors may have the potential to express both erythroid and non-erythroid species. These data indicated that several mRNA species of beta-spectrin could be detected in both erythroid and some non-erythroid cells. Whether multiple spectrin peptides could also be found with functional heterogeneity is unclear. However, in each case, the pattern combination observed appeared to be tissue-specific.
血影蛋白是红细胞骨架膜的主要蛋白质。最近,在各种非红细胞组织中也发现了同源但不相同的血影蛋白(肌动蛋白)。通过与人α-血影蛋白、β-血影蛋白(红细胞血影蛋白)和α-肌动蛋白(非红细胞血影蛋白)cDNA探针直接杂交,检测了红细胞和各种非红细胞中的血影蛋白mRNA。对聚腺苷酸加尾RNA的Northern印迹分析揭示了红细胞与非红细胞中不同的表达模式。从早期成红细胞到网织红细胞阶段的红细胞表达两种β-血影蛋白mRNA,而它们只表达一种α-血影蛋白,且不表达α-肌动蛋白mRNA。相比之下,非红细胞(血小板、髓细胞、肝脏、肌肉、心脏、小脑和晶状体)要么不表达α-血影蛋白mRNA,要么表达该基因不同分子量的转录本,以及一种α-肌动蛋白mRNA。此外,它们还表达从无到多种β-血影蛋白,且这些β-血影蛋白的分子大小与红细胞中的不同(血小板除外)。非红细胞血影蛋白α-肌动蛋白的转录本仅在非红细胞组织中以单拷贝形式存在。人和鼠的红白血病细胞除了表达α-肌动蛋白外,还表达两种红细胞血影蛋白转录本,这增加了红细胞祖细胞可能具有同时表达红细胞和非红细胞血影蛋白的潜力。这些数据表明,在红细胞和一些非红细胞中都能检测到几种β-血影蛋白mRNA。目前尚不清楚是否也能发现具有功能异质性的多种血影蛋白肽。然而,在每种情况下,观察到的模式组合似乎具有组织特异性。