The retinitis pigmentosa mutation c.3444+1G>A in CNGB1 results in skipping of exon 32.
The retinitis pigmentosa mutation c.3444+1G>A in CNGB1 results in skipping of exon 32.
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DOI：
10.1371/journal.pone.0008969
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发表时间：
2010-01-29
期刊：
影响因子：
3.7
通讯作者：
Michalakis S
中科院分区：
文献类型：
--
作者：
Becirovic E;Nakova K;Hammelmann V;Hennel R;Biel M;Michalakis S
视网膜色素变性是一种严重的遗传性眼病，其特征是光感受器的进行性退化和随后的视力丧失。在编码杆状环核苷酸门控通道(CNGB1a)B亚单位的CNGB1基因中发现了两个与RP相关的突变。其中一个(c.3444+1G>；A)位于32号外显子的供体位置，被认为导致相应蛋白质最后28个氨基酸的移码和截断。然而，这个模棱两可的结论并没有得到实验数据的验证。最近，另一项研究报道，CNGB1a的最后28个氨基酸含有一个基序，该基序需要适当的靶向该亚单位来杆状光感受器外节段。这表明靶向缺陷是影响患者RP表型的主要原因。在这里，我们通过外显子捕获实验研究了C.3444+1G>；A的剪接，并可以证明这种突变导致CNGB1a的最后170个氨基酸被68个无关的氨基酸取代，而不是建议的最后28个氨基酸的截断。170aa的缺失覆盖了完整的远端C末端，包括α1a配体结合域中一个重要的α(CNGB1a)螺旋的最后10个氨基酸。当在异源表达系统中表达时，与野生型相比，相应的突变体全长CNGB1a亚基更容易被蛋白酶体降解。总之，我们的实验数据不支持原始研究提出的关于C.3444+1G>；A突变的假说。基于这一点，我们认为，除了靶向缺陷之外，其他机制可能是受影响个体的RP表型的原因。
Retinitis pigmentosa (RP) is a severe hereditary eye disorder characterized by progressive degeneration of photoreceptors and subsequent loss of vision. Two of the RP associated mutations were found in the CNGB1 gene that encodes the B subunit of the rod cyclic nucleotide-gated channel (CNGB1a). One of them (c.3444+1G>A) is located at the donor site of exon 32 and has been proposed to result in a frameshift and truncation of the last 28 aa of the corresponding protein. However, this ambiguous conclusion was not verified by experimental data. Recently, another study reported that the last 28 aa of CNGB1a harbor a motif required for the proper targeting of this subunit to rod photoreceptor outer segments. This suggests that defective targeting is the major cause for the RP phenotype in affected patients. Here, we investigated the splicing of c.3444+1G>A by exon trapping experiments and could demonstrate that instead of the proposed truncation of the last 28 aa this mutation leads to replacement of the last 170 aa of CNGB1a by 68 unrelated amino acids. The 170 aa deletion covers the complete distal C-terminus including the last 10 aa of an important alpha (αC) helix within the ligand-binding domain of CNGB1a. When expressed in a heterologous expression system the corresponding mutant full-length CNGB1a subunit was more susceptible to proteosomal degradation compared to the wild-type counterpart. In conclusion, our experimental data do not support the hypothesis proposed by the original study on the c.3444+1G>A mutation. Based on this, we suggest that apart from the defective targeting other mechanisms may be responsible for the RP phenotype in affected individuals.
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影响因子：
3.4
作者：
Pagès, F;IIdefonse, M;Bennett, N
通讯作者：
Bennett, N
影响因子：
4.8
作者：
Colville, CA;Molday, RS
通讯作者：
Molday, RS
影响因子：
3.4
作者：
Mazzolini, M;Punta, M;Torre, V
通讯作者：
Torre, V
DOI：
10.1126/science.1169789
发表时间：
2009-03-20
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Kizhatil K;Baker SA;Arshavsky VY;Bennett V
通讯作者：
Bennett V
影响因子：
16.2
作者：
Matulef, K;Zagotta, WN
通讯作者：
Zagotta, WN