de Serres F J
Center for Life Sciences and Toxicology, Research Triangle Park, NC 27709-2194.
Mutat Res. 1989 Mar;211(1):89-102. doi: 10.1016/0027-5107(89)90109-7.
Genetic fine structure analysis of the ad-3 and immediately adjacent genetic regions was made by means of complementation tests on all possible pairwise combinations of 50 X-ray-induced irreparable adenine-3 mutants (designated ad-3IR). All mutants were induced in either heterokaryon 11 or heterokaryon 12 of Neurospora crassa, 2-component heterokaryons heterozygous for mutants at the 3 closely linked loci ad-3A and ad-3B and nic-2 (nicotinamide-requiring) located about 5.0 map units distal to ad-3B. The complementation tests involved mutants of the following genotypes: 15 ad-3A, 27 ad-3B, 7 ad-3A ad-3B nic-2 and 1 ad-3B nic-2. To facilitate mapping, 5 additional strains (each consisting of a gene/point mutation at the ad-3A or ad-3B locus and a separate site of closely linked recessive lethal damage in the immediately adjacent regions [designated ad-3R + RLCL]) were also included. The data from these complementation tests showed that the majority (46/50) of X-ray-induced irreparable ad-3 mutants mapped as a series of overlapping multilocus deletions that extend both proximally and distally into the immediately adjacent genetic regions, as well as into the 'X' region (a region of unknown, but essential function) between ad-3A and ad-3B. The remaining mutants (4/50) were found to result from a series of closely linked, but separate, mutations (designated multilocus mutations) of the type ad-3IR + RLCL, different from those found in previous studies (de Serres, 1968; de Serres and Brockman, 1968). The data from the present complementation tests have expanded the process of genetic fine structure mapping of the ad-3 and immediately adjacent regions (de Serres, 1968) and defined the presence of the following 11 genetic loci: (a) 4 loci (with either known [i.e. col-1t] or unknown [i.e. unknA]) function proximal to ad-3A: unknA, unknB, col-1t, and col-2t, (b) 4 loci in the 'X' region: unknC, unknD, unknE, and unknF, (c) 2 loci distal to ad-3B: unknG, col-3t, and (d) 1 locus distal to nic-2: unknH.
通过对50个X射线诱导的不可修复的腺嘌呤-3突变体（称为ad-3IR）的所有可能成对组合进行互补测试，对ad-3及其紧邻的遗传区域进行了遗传精细结构分析。所有突变体均在粗糙脉孢菌的异核体11或异核体12中诱导产生，这两个双组分异核体在紧密连锁的3个位点ad-3A、ad-3B和位于ad-3B远端约5.0个图距的nic-2（需要烟酰胺）处杂合有突变体。互补测试涉及以下基因型的突变体：15个ad-3A、27个ad-3B、7个ad-3A ad-3B nic-2和1个ad-3B nic-2。为便于定位，还纳入了另外5个菌株（每个菌株在ad-3A或ad-3B位点由一个基因/点突变以及紧邻区域中紧密连锁的隐性致死损伤的一个单独位点组成[称为ad-3R + RLCL]）。这些互补测试的数据表明，大多数（46/50）X射线诱导的不可修复的ad-3突变体定位为一系列重叠的多位点缺失，这些缺失向近端和远端延伸到紧邻区域，以及延伸到ad-3A和ad-3B之间的“X”区域（一个功能未知但必不可少的区域）。其余突变体（4/50）被发现是由一系列紧密连锁但相互独立的突变（称为多位点突变）导致的，类型为ad-3IR + RLCL，与先前研究（de Serres，1968；de Serres和Brockman，1968）中发现的不同。当前互补测试的数据扩展了ad-3及其紧邻区域的遗传精细结构定位过程（de Serres，1968），并确定了以下11个遗传位点的存在：(a) 4个位于ad-3A近端的位点（功能已知的[即col-1t]或未知的[即unknA]）：unknA、unknB、col-1t和col-2t，(b) “X”区域中的4个位点：unknC、unknD、unknE和unknF，(c) 2个位于ad-3B远端的位点：unknG、col-3t，以及(d) 1个位于nic-2远端的位点：unknH。
