PAX6, paired domain influences sequence recognition by the homeodomain
PAX6, paired domain influences sequence recognition by the homeodomain
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DOI：
10.1074/jbc.m206478200
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发表时间：
2002-12-20
影响因子：
4.8
通讯作者：
Saunders, GF
中科院分区：
文献类型：
--
作者：
Mishra, R;Gorlov, IP;Saunders, GF
Pax6具有转录因子的功能，有两个DNA结合域，配对结构域(PD)和同源结构域(111)，由富含甘氨酸的接头连接，在C末端有一个富含脯氨酸-丝氨酸-苏氨酸(PST)的反式激活区。PAX6的功能机制目前还不清楚，在脊椎动物中发现的靶基因也很少。在这份报告中，我们描述了患者从PAX6的配对结构域区域和Pax6的配对的无结构域(PD-less)亚型(PD-less)中错义突变的功能分析，该亚型缺乏配对的结构域和部分富含甘氨酸的接头。在小鼠的脑、眼和胰腺中均有PD表达。该亚型在脑中的表达水平相对较高。突变位点PAX6-L46R和-C52R位于PAX6选择性剪接体PAX6-5a的5a-多肽插入物的两端。本报告中描述的另一个PAX6突变体V53L与C5211相邻。我们在PAX6和PAX65a中创建了相应的突变，并评估了它们的转录激活和DNA结合特性。PAX6的PD突变体(L46R、C52R和V53L)表现出比野生型PAX6更低的反式激活活性和可变的DNA结合能力。含有PAX6-5a亚型的突变氨基酸在含有HD DNA结合序列的报告中显示出意想不到的反式激活特性。PAX65a-C52R和-V53L的反式激活活性较低，但PAX6-5a-L46R的反式激活能力强于PAX6-5a。无PD的Pax6亚型失去了反式激活能力，但可以与HD DNA结合序列结合。对Pax6无PD亚型的功能分析以及与PD错义突变相关的发现表明，PAX6的PD是HD功能所必需的。
PAX6 functions as a transcription factor and has two DNA-binding domains, a paired domain (PD) and a homeodomain (111)), joined by a glycine-rich linker and followed by a proline-serine-threonine-rich (PST) trans-activation region at the C terminus. The mechanism of PAX6 function is not clearly understood, and few target genes in vertebrates have been identified. In this report we described the functional analyses of patient missense mutations from the paired domain region of PAX6 and a paireddomain-less isoform (PD-less) of Pax6 that lacks the paired domain and part of the glycine-rich linker. The PD-less was expressed in the brain, eyes, and pancreas of mouse. The level of expression of this isoform was relatively higher in brain. The mutation sites PAX6-L46R and -C52R were located in the PD of PAX6 on either end of the 5a-polypeptide insert of the alternatively spliced form of PAX6, PAX6-5a. Another PAX6 mutant V53L described in this report was adjacent to C5211. We created corresponding mutations in PAX6 and PAX65a, and evaluated their transcriptional activation and DNA binding properties. The PD mutants of PAX6 (L46R, C52R, and V53L) exhibited lower transactivation activities and variable DNA binding ability than wildtype PAX6 with PD DNA-binding consensus sequences. The mutated amino acids containing PAX6-5a isoforms showed unexpected transactivation properties with a reporter containing HD DNA-binding sequences. PAX65a-C52R, and -V53L showed lower transactivation activities, but PAX6-5a-L46R had greater transactivation ability than PAX6-5a. The PD-less isoform of Pax6 lost its transactivational ability but could bind to the HD DNA-binding sequences. Functional analysis of the PD-less isoform of Pax6 as well as findings related to missense mutations in the PD suggest that the PD of PAX6 is required for HD function.