谷子B3转录因子可变剪切体分析

Analysis of the B3 transcription factor alternative splicer in foxtail millet(Setaria italica L.)

通过分析不同谷子品种B3转录因子基因存在的可变剪切类型,鉴定出具有功能活性的可变剪切体,并分析这些可变剪切体与谷子抽穗期是否具有相关性,为深入揭示B3转录因子可变剪切对谷子生长发育的调控作用提供依据。选择12份不同抽穗期的谷子材料,利用反转录PCR(reverse transcription PCR, RT-PCR)技术克隆了一个REM家族的B3转录因子基因,通过序列比对鉴定该基因存在的可变剪切体类型,分析这些可变剪切体的活性及其与抽穗期的关系。结果表明,B3转录因子基因在这12个谷子品种间共产生了8种可变剪切体,其中可变剪切体Ⅴ包含的品种最多(4个),其次为可变剪切体Ⅳ(2个),其余6种可变剪切体均只包含1个品种。通过可变剪切,12个品种的B3转录因子基因共可编码10种蛋白质,其中5种蛋白质缺失B3 DNA结合域;Ⅱ型蛋白质具有缩短谷子抽穗期的功能,Ⅵ型蛋白质具有延长谷子抽穗期的功能,且这种作用不受地理环境影响。以上结果表明,B3转录因子通过可变剪切参与谷子抽穗期的调控。

The alternative splicing types of B3 transcriptional factor gene in different millet varieties were analyzed to identify the splicing variants with functional activity.Furthermore,the correlation between these splicing variants and heading stage was analyzed,aiming at providing evidence for further revealing the regulatory effects of B3 transcription factor on growth and development of millet by alternative splicing.Totally 12 millet varieties with different heading stages were selected to clone B3 transcriptional factor gene belonging to REM family by reverse transcription PCR(RT-PCR).The alternative splicing types of this gene were identified by multiple sequence alignment,and the activity of the splicing variants,their association with heading stage were analyzed.The results showed that a total of 8 splicing variants of B3 transcriptional factor gene were produced among the 12 millet varieties,of which splicing variantⅤcontained the most varieties(4),followed by splicing variantⅣ(2),and the remaining 6 splicing variants each contained only 1 variety.By alternative splicing,the B3 transcriptional factor gene of 12 varieties encoded 10 types of proteins,of which 5 types lacked the B3 DNA binding domain,and typeⅡprotein shortened the heading stage of millet,while typeⅥprotein prolonged the heading stage of millet,which was not affected by geographical environments.The above results showed that B3 transcription factor participated in the regulation of heading stage through alternative splicing in millet.