Zhou L W, Haas H, Marzluf G A
Department of Biochemistry, The Ohio State University, Columbus 43210, USA.
Mol Gen Genet. 1998 Sep;259(5):532-40. doi: 10.1007/s004380050845.
Multiple GATA factors - regulatory proteins with consensus zinc finger motifs that bind to DNA elements containing a GATA core sequence - exist in the filamentous fungus Neurospora crassa. One GATA factor, NIT2. controls nitrogen metabolism, whereas two others, WC-1 and WC-2, regulate genes responsive to blue light induction. A gene encoding a new GATA factor, named SRE, was isolated from Neurospora using a PCR-mediated method. Sequence analysis of the new GATA factor gene revealed an ORF specifying 587 amino acids, which is interrupted by two small introns. Unlike all previously known Neurospora GATA factors, which possess a single zinc-finger DNA-binding motif, SRE contains two GATA-type zinc fingers. The deduced amino acid sequence of SRE shows significant similarity to URBSI of Ustilago and SREP of Penicillium. A loss-of-function mutation was created by the RIP procedure. Analysis of sre+ and sre- strains revealed that SRE acts as a negative regulator of iron uptake in Neurospora by controlling the synthesis of siderophores. Siderophore biosynthesis is repressed by high iron concentrations in the wild-type strain but not in sre- mutant cells. The sre promoter contains a number of GATA sequences; however, expression of sre mRNA occurs in a constitutive fashion and is not regulated by the concentration of iron available to the cells.
在丝状真菌粗糙脉孢菌中存在多种GATA因子，即具有共有锌指基序的调控蛋白，可与含有GATA核心序列的DNA元件结合。其中一个GATA因子NIT2控制氮代谢，而另外两个，WC - 1和WC - 2则调控对蓝光诱导有反应的基因。利用PCR介导的方法从脉孢菌中分离出一个编码新GATA因子的基因，命名为SRE。对新GATA因子基因的序列分析揭示了一个编码587个氨基酸的开放阅读框，该开放阅读框被两个小内含子打断。与所有先前已知的脉孢菌GATA因子不同，这些因子都具有单个锌指DNA结合基序，而SRE含有两个GATA型锌指。推导的SRE氨基酸序列与黑粉菌的URBSI和青霉菌的SREP有显著相似性。通过RIP程序产生了功能缺失突变。对sre +和sre -菌株的分析表明，SRE通过控制铁载体的合成，作为脉孢菌中铁摄取的负调节因子。在野生型菌株中，高铁浓度会抑制铁载体的生物合成，但在sre -突变细胞中则不会。sre启动子包含许多GATA序列；然而，sre mRNA的表达以组成型方式发生，不受细胞可利用铁浓度的调节。
