Burr F A, Burr B, Scheffler B E, Blewitt M, Wienand U, Matz E C
Biology Department, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
Plant Cell. 1996 Aug;8(8):1249-59. doi: 10.1105/tpc.8.8.1249.
The recessive mutation intensifier1 of maize apparently causes an overall increase in flavonoid production in the aleurone. The mechanism by which this is achieved is not understood. We have succeeded in cloning the intensifier1 gene by transposon tagging with Suppressor-mutator and found, by sequence analyses, that it shares homology with known transcription factors in the anthocyanin pathway, in particular the r1/b1 multigene family in maize. Two cDNAs and a genomic clone were completely sequenced, and together they showed that the transcripts were misspliced. The frequency of missplicing was investigated by polymerase chain reaction analyses and sequencing of the individual introns. These studies indicate that very little functional transcript was made. Indeed, missplicing may be a mechanism for reducing the levels of a transcription factor that, when present, acts as a repressor of anthocyanin biosynthesis.
玉米的隐性突变增强子1显然会导致糊粉层中类黄酮产量整体增加。实现这一过程的机制尚不清楚。我们通过使用抑制子突变体进行转座子标签法成功克隆了增强子1基因，并通过序列分析发现，它与花青素途径中已知的转录因子具有同源性，特别是玉米中的r1/b1多基因家族。对两个cDNA和一个基因组克隆进行了完全测序，结果表明转录本存在错误剪接。通过聚合酶链反应分析和对各个内含子进行测序，研究了错误剪接的频率。这些研究表明，产生的功能性转录本非常少。实际上，错误剪接可能是一种降低转录因子水平的机制，该转录因子在存在时会作为花青素生物合成的抑制因子起作用。
