Ballario P, Talora C, Galli D, Linden H, Macino G
Dipartimento di Genetica e Biologia Molecolare, Centro di Studio per gli Acidi Nucleici, Università di Roma La Sapienza, Rome, Italy.
Mol Microbiol. 1998 Aug;29(3):719-29. doi: 10.1046/j.1365-2958.1998.00955.x.
The genes coding for white collar-1 and white collar-2 (wc-1 and wc-2) have been isolated previously, and their products characterized as Zn-finger transcription factors involved in the control of blue light-induced genes. Here, we show that the PAS dimerization domains present in both proteins enable the WC-1 and WC-2 proteins to dimerize in vitro. Homodimers and heterodimers are formed between the white collar (WC) proteins. A computer analysis of WC-1 reveals a second domain, called LOV, also identified in NPH1, a putative blue light photoreceptor in plants and conserved in redox-sensitive proteins and in the phytochromes. The WC-1 LOV domain does not dimerize with canonical PAS domains, but it is able to self-dimerize. The isolation of three blind wc-1 strains, each with a single amino acid substitution only in the LOV domain, reveals that this region is essential for blue light responses in Neurospora. The demonstration that the WC-1 proteins in these LOV mutants are still able to self-dimerize suggests that this domain plays an additional role, essential in blue light signal transduction.
编码白领-1和白领-2（wc-1和wc-2）的基因先前已被分离出来，其产物被鉴定为参与蓝光诱导基因调控的锌指转录因子。在此，我们表明这两种蛋白质中存在的PAS二聚化结构域能够使WC-1和WC-2蛋白在体外二聚化。白领（WC）蛋白之间形成同型二聚体和异型二聚体。对WC-1的计算机分析揭示了另一个结构域，称为LOV，在NPH1中也有发现，NPH1是植物中一种假定的蓝光光感受器，在对氧化还原敏感的蛋白质和植物色素中保守。WC-1的LOV结构域不与典型的PAS结构域二聚化，但它能够自我二聚化。分离出三个失明的wc-1菌株，每个菌株仅在LOV结构域中有一个氨基酸替换，这表明该区域对于粗糙脉孢菌的蓝光反应至关重要。这些LOV突变体中的WC-1蛋白仍能自我二聚化，这一证明表明该结构域发挥了额外的作用，在蓝光信号转导中必不可少。
