Martínez-Abarca F, García-Rodríguez F M, Toro N
Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Granada, Spain.
Mol Microbiol. 2000 Mar;35(6):1405-12. doi: 10.1046/j.1365-2958.2000.01804.x.
RmInt1 is a functional group II intron found in Sinorhizobium meliloti where it interrupts a group of IS elements of the IS630-Tc1 family. In contrast to many other group II introns, the intron-encoded protein (IEP) of RmInt1 lacks the characteristic conserved part of the Zn domain associated with the IEP endonuclease activity. Nevertheless, in this study, we show that RmInt1 is capable of inserting into a vector containing the DNA spanning the RmInt1 target site from the genome of S. meliloti. Efficient homing was also observed in the absence of homologous recombination (RecA- strains). In addition, it is shown that RmInt1 is able to move to its target in a heterologous host (S. medicae). Homing of RmInt1 occurs very efficiently upon DNA target uptake (conjugation/electroporation) by the host cell resulting in a proportion of invaded target of 11-30%. Afterwards, the remaining intronless target DNA is protected from intron invasion.
RmInt1是在苜蓿中华根瘤菌中发现的一个II类功能性内含子，它打断了IS630 - Tc1家族的一组IS元件。与许多其他II类内含子不同，RmInt1的内含子编码蛋白（IEP）缺乏与IEP内切核酸酶活性相关的锌结构域的特征性保守部分。然而，在本研究中，我们表明RmInt1能够插入到一个载体中，该载体包含来自苜蓿中华根瘤菌基因组的跨越RmInt1靶位点的DNA。在没有同源重组（RecA - 菌株）的情况下也观察到了高效归巢。此外，研究表明RmInt1能够转移到异源宿主（中慢生根瘤菌）中的靶位点。当宿主细胞摄取DNA靶标（接合/电穿孔）时，RmInt1的归巢非常高效，导致11 - 30%的入侵靶标比例。之后，剩余的无内含子靶标DNA受到保护，免受内含子入侵。
