Primary structural features of the S haplotype-specific F-box protein, SFB, in Prunus
Primary structural features of the S haplotype-specific F-box protein, SFB, in Prunus
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DOI：
10.1007/s00497-003-0200-x
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发表时间：
2004-01-01
影响因子：
--
通讯作者：
Tao, R
中科院分区：
文献类型：
--
作者：
Ikeda, K;Igic, B;Tao, R
SFB 基因编码一种 F-box 蛋白，该蛋白具有适当的 S 单倍型特异性变异，可作为李属（蔷薇科）基于 S-RNase 的配子体自交不亲和性 (GSI) 反应中的花粉决定因素。为了进一步表征李属 SFB，我们克隆并测序了来自甜樱桃 (P. avium) 的另外四个等位基因：SFB1、SFB2、SFB4 和 SFB5。这四个等位基因显示出与已克隆的其他九个 SFB 等位基因相似的单倍型特异性序列多样性。在李属 SFB 的氨基酸比对中，包括四个新克隆的等位基因，384 个位点中的 121 个位点是保守的，另外 65 个位点仅具有保守替换。 SFB 之间的氨基酸同一性范围为 66.0% 至 82.5%。根据标准化变异指数 (NVI)，34 个非保守位点被认为是高度变异的。大多数可变位点位于 C 末端区域。 NVI 的窗口平均图表明存在两个可变区域和两个高变区域。这些可变区和高变区似乎是亲水性的或至少不是强疏水性的，这表明这些区域可能暴露在表面上并在 GSI 反应的等位基因特异性中发挥作用。使用最大似然法检测正选择的证据，正选择位点集中在可变区和高变区。
The gene SFB encodes an F-box protein that has appropriate S-haplotype-specific variation to be the pollen determinant in the S-RNase-based gametophytic self-incompatibility (GSI) reaction in Prunus (Rosaceae). To further characterize Prunus SFB, we cloned and sequenced four additional alleles from sweet cherry (P. avium), SFB1, SFB2, SFB4, and SFB5. These four alleles showed haplotype-specific sequence diversity similar to the other nine SFB alleles that have been cloned. In an amino acid alignment of Prunus SFBs, including the four newly cloned alleles, 121 out of the 384 sites were conserved and an additional 65 sites had only conservative replacements. Amino acid identity among the SFBs ranged from 66.0% to 82.5%. Based on normed variability indices (NVI), 34 of the non-conserved sites were considered to be highly variable. Most of the variable sites were located at the C-terminal region. A window-averaged plot of NVI indicated that there were two variable and two hypervariable regions. These variable and hypervariable regions appeared to be hydrophilic or at least not strongly hydrophobic, which suggests that these regions may be exposed on the surface and function in the allele specificity of the GSI reaction. Evidence of positive selection was detected using maximum likelihood methods with sites under positive selection concentrated in the variable and hypervariable regions.