WhiD and WhiB, homologous proteins required for different stages of sporulation in Streptomyces coelicolor A3(2)
WhiD and WhiB, homologous proteins required for different stages of sporulation in Streptomyces coelicolor A3(2)
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DOI：
10.1128/jb.182.5.1286-1295.2000
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发表时间：
2000-03-01
影响因子：
3.2
通讯作者：
Buttner, MJ
中科院分区：
文献类型：
--
作者：
Molle, V;Palframan, WJ;Buttner, MJ
将天蓝色链霉菌气生菌丝分化成成熟孢子链所需的whiD基因座通过基于图位的克隆定位于Redenbach等人的最小有序文库的cosmoprotein 6 G4和D 63之间的重叠（M，Redenbach等人，摩尔Microbiol. 21：77-96，1996），亚克隆和测序显示whiD编码WhiB的同源物，WhiB是S.天蓝色。WhiD和WhiB属于一个不断增长的小家族（76至112个残基）蛋白质，其生化功能未知，其中4个半胱氨酸是绝对保守的;该家族的所有已知成员都在放线菌中发现。构建的whiD无效突变体表现出孢子形成水平降低，并且那些农场的孢子是热敏感的，广泛裂解的，并且尺寸高度不规则，至少部分地由隔膜放置的不规则性引起。whiD无效突变体表现出极端的变化孢子细胞壁沉积;大多数孢子均匀薄（20- 30纳米）的墙壁，但孢子链中经常观察到有不规则的，但非常明显的（高达170纳米）下降壁增厚孢子之间的连接处。whiD无效突变体孢子经常通过附加隔膜的沉积而被划分成不规则的较小单位，这些隔膜通常位于几个不同的平面上，非常接近孢子极。这些“小染色体”似乎缺乏染色体DNA。鉴定了两个whiD启动子whiDp 1和whiDp 2，并分析了它们在野生型S.这两种启动子都受到发育调控; whiDp 1和whiDp 2转录本是瞬时检测到的，大约在气生菌丝中观察到孢子形成隔膜的时候。
The whiD locus, which is required for the differentiation of Streptomyces coelicolor aerial hyphae into mature spore chains, was localized by map-based cloning to the overlap between cosmids 6G4 and D63 of the minimal ordered library of Redenbach et al, (M, Redenbach et al., Mol. Microbiol. 21:77-96, 1996), Subcloning and sequencing showed that whiD encodes a homologue of WhiB, a protein required for the initiation of sporulation septation in S. coelicolor. WhiD and WhiB belong to a growing family of small (76- to 112-residue) proteins of unknown biochemical function in which four cysteines are absolutely conserved; all known members of this family are found in the actinomycetes. A constructed whiD null mutant showed reduced levels of sporulation, and those spores that did farm were heat sensitive, lysed extensively, and were highly irregular in size, arising at least in part from irregularity in septum placement. The whiD null mutant showed extreme variation in spore cell wall deposition; most spores had uniformly thin (20- to 30-nm) walls, but spore chains were frequently observed in which there was irregular but very pronounced (up to 170 nm) fell wall thickening at the junctions between spores. whiD null mutant spores were frequently partitioned into irregular smaller units through the deposition of additional septa, which were often laid down in several different planes, very close to the spore poles. These "minicompartments" appeared to be devoid of chromosomal DNA. Two whiD promoters, whiDp1 and whiDp2, were identified, and their activities were analyzed during development of wild-type S. coelicolor on solid medium, Both promoters were developmentally regulated; whiDp1 and whiDp2 transcripts were detected transiently, approximately at the time when sporulation septa were observed in the aerial hyphae.