EXPRESSION OF FERROCHELATASE MESSENGER-RNA IN ERYTHROID AND NONERYTHROID CELLS
EXPRESSION OF FERROCHELATASE MESSENGER-RNA IN ERYTHROID AND NONERYTHROID CELLS
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DOI：
10.1042/bj2920343
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发表时间：
1993-06-01
影响因子：
4.1
通讯作者：
PONKA, P
中科院分区：
文献类型：
--
作者：
CHAN, RYY;SCHULMAN, HM;PONKA, P
铁螯合酶催化血红素生物合成的最后一步，即将 Fe(II) 插入原卟啉 IX，它存在于所有细胞中，但在血红蛋白化过程中在红细胞中特别丰富。使用小鼠亚铁螯合酶cDNA作为探针，在小鼠肝、肾、脑、肌肉和脾的提取物中发现了两种亚铁螯合酶转录物，长度分别为2.9 kb和2.2 kb，其中2.9 kb转录物在非红细胞组织中更为丰富，2.2 kb转录物在脾脏中更为主要。在小鼠红白血病细胞中，2.9 kb 亚铁螯合酶转录物也更丰富；然而，在二甲亚砜诱导红细胞分化后，2.2 kb 转录物优先增加，最终占主导地位。对于小鼠网织红细胞（现有的最纯的未成熟红系细胞群），超过 90% 的总亚铁螯合酶 mRNA 以 2.2 kb 转录物形式存在。由于可能只有一个小鼠亚铁螯合酶基因，因此亚铁螯合酶 DNA 3' 区域中两个推定的聚腺苷酸化信号的使用可能会导致两个亚铁螯合酶转录物的出现。通过使用 PCR 产生的 389 bp DNA 片段以及与聚腺苷酸化位点之间的区域具有序列相似性的合成寡引物来探索这种可能性。该片段仅与 2.9 kb 亚铁螯合酶转录物杂交，表明两个转录物在 3' 末端不同，并表明 2.2 kb 转录物是利用上游聚腺苷酸化信号的结果。上游聚腺苷酸化信号的优先利用可能是亚铁螯合酶基因表达的红细胞特异性特征。
Ferrochelatase, which catalyses the last step in haem biosynthesis, i.e. the insertion of Fe(II) into protophorphyrin IX, is present in all cells, but is particularly abundant in erythroid cells during haemoglobinization. Using mouse ferrochelatase cDNA as a probe two ferrochelatase transcripts, having lengths of 2.9 kb and 2.2 kb, were found in extracts of mouse liver, kidney, brain, muscle and spleen, the 2.9 kb transcript being more abundant in the non-erythroid tissues and the 2.2 kb transcript more predominant in spleen. In mouse erythroleukemia cells the 2.9 kb ferrochelatase transcript is also more abundant; however, following induction of erythroid differentiation by dimethyl sulphoxide there is a preferential increase in the 2.2 kb transcript, which eventually predominates. With mouse reticulocytes, the purest immature erythroid cell population available, over 90% of the total ferrochelatase mRNA is present as the 2.2 kb transcript. Since there is probably only one mouse ferrochelatase gene, the occurrence of two ferrochelatase transcripts could arise from the use of two putative polyadenylation signals in the 3' region of ferrochelatase DNA. This possibility was explored by using a 389 bp DNA fragment produced by PCR with synthetic oligoprimers having sequence similarity with a region between the polyadenylation sites. This fragment hybridized only to the 2.9 kb ferrochelatase transcript, indicating that the two transcripts differ at their 3' ends and suggesting that the 2.2 kb transcript results from the utilization of the upstream polyadenylation signal. The preferential utilization of the upstream polyadenylation signal may be an erythroid-specific characteristic of ferrochelatase gene expression.