Department of Microbiology, University of Georgia, Athens, Georgia 30602.
Proc Natl Acad Sci U S A. 1983 Mar;80(5):1406-10. doi: 10.1073/pnas.80.5.1406.
The product(s) of the Myxococcus xanthus spoC locus is required for two multicellular activities in fruiting body development, rippling and sporulation. Ripples, which are formed early in development, are spatially separated ridges of cells that move synchronously. Myxospores are heat-resistant resting cells that are formed near the end of the developmental process. To investigate the function of spoC, it was cloned in an Escherichia coli plasmid, then transferred to M. xanthus by specialized transduction with coliphage P1. The plasmid, which cannot replicate in M. xanthus, integrated into the M. xanthus chromosome, producing two copies of the spoC locus in tandem. Cells containing one copy of a mutant allele and one copy of the wild-type allele displayed the wild-type phenotype. Cells containing two different mutant alleles failed to ripple or sporulate, implying that all four independent spoC mutations are in the same gene or unit of transcription. Homozygous mutant duplications arose from constructions in which DNA from a spo(+) donor was transduced into a spoC recipient, or vice versa, at an average frequency of 14%, indicating that gene conversion was a frequent event.
粘球菌 spoC 基因座的产物对于子实体发育过程中的两种多细胞活动，即波纹形成和孢子形成，是必需的。波纹形成是发育早期形成的、细胞同步移动的空间分离脊。粘孢子是耐热的休眠细胞，在发育过程接近尾声时形成。为了研究 spoC 的功能，它被克隆到大肠杆菌质粒中，然后通过噬菌体 P1 的专门转导转移到粘球菌中。该质粒不能在粘球菌中复制，整合到粘球菌染色体中，产生两个串联的 spoC 基因座的拷贝。含有一个突变等位基因和一个野生型等位基因拷贝的细胞表现出野生型表型。含有两个不同突变等位基因的细胞不能形成波纹或产生孢子，这意味着所有四个独立的 spoC 突变都在同一个基因或转录单位中。来自 spo(+)供体的 DNA 通过噬菌体转导到 spoC 受体，或者反之，在 spoC 受体中，同源突变体的纯合重复发生的频率平均为 14%，表明基因转换是一个频繁发生的事件。
