McClung C R
Department of Biological Sciences, Dartmouth College, Hanover, NH 03755, USA.
Free Radic Biol Med. 1997;23(3):489-96. doi: 10.1016/s0891-5849(97)00109-3.
The catalase multi-gene family in Arabidopsis includes three genes encoding individual subunits which associate to form at least six isozymes that are readily resolved by non-denaturing gel electrophoresis. CAT1 and CAT3 map to chromosome 1, and CAT2 maps to chromosome 4. The nucleotide and deduced amino acids sequences of the three coding regions are highly related to each other and to other catalases. Both the individual isozymes and the individual subunit mRNAs show distinct patterns of spatial (organ-specific) expression. Six isozymes are detected in flowers and leaves and two are seen in roots. All three mRNAs are highly expressed in inflorescences, and CAT2 and CAT3 are highly expressed in leaves. All three mRNAs are detectable in freshly imbibed seeds, although the pattern of mRNA relative abundance varies among the three genes during early germination. CAT1 and CAT2 mRNA abundance is induced by light. In contrast, CAT3 is negatively light-responsive. CAT2 and CAT3 mRNA abundance is controlled by the circadian clock. Interestingly, the peak in CAT3 mRNA abundance occurs in the subjective evening, which is out of phase with expression of the Arabidopsis CAT2 catalase gene that shows clock-regulated expression gated to the subjective early morning. CAT1 mRNA abundance is not clock-regulated.
拟南芥中的过氧化氢酶多基因家族包括三个编码单个亚基的基因，这些亚基相互结合形成至少六种同工酶，可通过非变性凝胶电泳轻松分离。CAT1和CAT3定位于1号染色体，CAT2定位于4号染色体。三个编码区的核苷酸和推导的氨基酸序列彼此高度相关，并且与其他过氧化氢酶也高度相关。单个同工酶和单个亚基mRNA均显示出不同的空间（器官特异性）表达模式。在花和叶中检测到六种同工酶，在根中检测到两种。所有三种mRNA在花序中均高度表达，CAT2和CAT3在叶中高度表达。在刚吸胀的种子中可以检测到所有三种mRNA，尽管在早期萌发过程中三种基因之间mRNA相对丰度的模式有所不同。CAT1和CAT2的mRNA丰度受光诱导。相反，CAT3对光呈负响应。CAT2和CAT3的mRNA丰度受昼夜节律时钟控制。有趣的是，CAT3 mRNA丰度的峰值出现在主观夜间，这与拟南芥CAT2过氧化氢酶基因的表达不同相，后者显示出受时钟调节的表达，在主观清晨达到峰值。CAT1的mRNA丰度不受时钟调节。
