Spatial and temporal divergence of expression in duplicated barley germin-like protein-encoding genes
Spatial and temporal divergence of expression in duplicated barley germin-like protein-encoding genes
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DOI：
10.1534/genetics.106.058156
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发表时间：
2006-09-01
期刊：
影响因子：
3.3
通讯作者：
Kaeppler, Heidi F.
中科院分区：
文献类型：
--
作者：
Federico, Maria L.;Iniguez-Luy, Federico L.;Kaeppler, Heidi F.
亚功能化是一对重复基因或旁系同源物经历个体表达模式或功能降低，同时仍然复制祖先基因的完整表达模式和功能的过程。GerB和GerF是大麦中的一个小基因家族的旁系同源基因。这两个基因在编码区和非编码区具有高度的核苷酸序列相似性，编码相同的质外体蛋白。使用RNA凝胶印迹，加上单链构象多态性（SSCP）分析的RT-PCR产物，阐明了每个基因的发育和组织特异性表达模式。个体表达模式提供了重叠冗余和早期亚功能化的证据。GerB主要在发育中的芽中表达，而GerF主要在幼苗根、发育中的穗和果皮/种皮中表达。GerF启动子缺失研究定位了负责高启动子活性的区域（-356/-97），并显示了GerB和GerF上游区域驱动gfp在发育穗的胚芽鞘、外果皮和外稃/内稃中表达的能力。所观察到的表达模式与该基因家族在植物发育和防御机制中的作用是一致的。这些作用可以解释为什么冗余一直选择性地保持在这个重复的基因对。
Subfunctionalization is the process by which a pair of duplicated genes, or paralogs, experiences a reduction of individual expression patterns or function while still reproducing the complete expression pattern and function of the ancestral gene. Two germin-like protein (GLP)-encoding genes, GerB and GerF, are paralogs that belong to a small gene family in barley (Hordeum vulgare). Both genes share high nucleotide sequence similarity in coding and noncoding regions and encode identical apoplastic proteins. The use of RNA gel blots, coupled with single-stranded conformation polymorphism (SSCP) analysis of RT-PCR products, elucidated the developmental and tissue-specific expression patterns of each gene. Individual expression patterns provided evidence of both overlapping redundancy and early subfunctionalization. GerB is predominantly expressed in developing shoots, while GerF is predominantly expressed in seedling roots, developing spikes, and pericarp/testa. GerF promoter deletion studies located a region (-356/-97) responsible for high promoter activity and showed the ability of GerB and GerF upstream regions to drive gfp expression in coleoptiles, epicarps, and lemma/palea of developing spikes. The observed expression patterns are consistent with proposed roles in plant development and defense mechanisms for this gene family. These roles may explain why redundancy has been selectively maintained in this duplicate gene pair.