INTER-NUCLEAR TRANSFER OF GENETIC INFORMATION IN KAR1-1-KAR1 HETEROKARYONS IN SACCHAROMYCES CEREVISIAE
INTER-NUCLEAR TRANSFER OF GENETIC INFORMATION IN KAR1-1-KAR1 HETEROKARYONS IN SACCHAROMYCES CEREVISIAE
复制标题
DOI：
10.1128/mcb.1.3.245
复制
发表时间：
1981-01-01
影响因子：
5.3
通讯作者：
DUTCHER, SK
中科院分区：
文献类型：
--
作者：
DUTCHER, SK
异核体S.利用kar 1 -1突变来构建酿酒酵母，kar 1 - 1突变防止接合期间的核融合。每个异核体含有2个在多条染色体上标记的单倍体核。他们分离了单倍体后代（细胞导入子），其中大多数具有异核体亲本中的一个或另一个的核基因型，但他们偶尔分离具有重组基因型的后代（例外的细胞导入子）。特殊的细胞导入子从一个亲本（受体）接受大部分基因组，从另一个亲本（供体）接受少数基因组。2个标记从供体核转移到受体对于位于不同染色体上的标记很少是一致的，但是对于位于相同染色体上的那些标记几乎总是一致的;这表明整个染色体从供体核转移到受体。在kar 1 - 1x的交叉中，KAR 1亲本，任何一个细胞核都可能以相等的概率充当受体或供体。10条染色体中，有9条被染色体核所获得，其频率与染色体的大小呈负相关。当一条染色体被受体细胞核获得时，它要么取代它的同源体，要么以二体状态存在。源自kar 1X的单倍体后代。KAR 1杂交通常是无效的。这种不活力可能是供体细胞核染色体丢失的结果。来自kar 1x的后代的存活力KAR 1异核体的改善时，父母的核二倍体的假设一致的程度，并已成为单体的二倍体后代从这些异核体回收。下列事件顺序说明了kar 1x中的染色体转移。KAR 1异核体。细胞融合后，异核体中的每个细胞核丢失一条或多条染色体的概率约为0.38。在染色体转移事件中，维持这种损失的细胞核可以成为供体。如果另一个细胞核没有承受致命的染色体丢失，它可以成为转移事件中的受体。获得供体丢失的染色体的机会对于较小的染色体比对于较大的染色体更大，并且对于平均染色体约为0.05。
Heterokaryons of S. cerevisiae were constructed utilizing the kar1-1 mutation, which prevents nuclear fusion during conjugation. Each heterokaryon contained 2 haploid nuclei that were marked on several chromosomes. They segregated haploid progeny (cytoductants), most of which have the nuclear genotype of one or the other of the heterokaryon parents, but they occasionally segregated progeny having a recombinant genotype (exceptional cytoductants). Exceptional cytoductants receive the majority of their genome from 1 parent (the recipient) and a minority from the other (the donor). Transfer of 2 markers from the donor nucleus to the recipient is rarely coincident for markers located on different chromosomes, but is nearly always coincident for those markers located on the same chromosome; this suggests that whole chromosomes are transferred from the donor nucleus to the recipient. In crosses of kar1-1 .times. KAR1 parents, either nucleus may act as a recipient or donor with equal probability. Recipient nuclei acquired 9 of the 10 chromosomes examined, with frequencies which were inversely correlated with the size of the chromosome. When a chromosome is acquired by the recipient nucleus, it either replaces its homolog or exists in a disomic condition. Haploid progeny emanating from kar1 .times. KAR1 crosses are frequently inviable. The possibility that this inviability might be the result of chromosome loss by donor nuclei was tested. Viability of progeny from kar1 .times. KAR1 heterokaryons was improved when the parental nuclei were diploid to an extent consistent with the hypothesis, and when diploid progeny which had become monosomic were recovered from these heterokaryons. The following sequence of events accounts for chromosome transfer in kar1 .times. KAR1 heterokaryons. After cell fusion, each nucleus in the heterokaryon has a probability of about 0.38 of losing one or more chromosomes. A nucleus sustaining such a loss can become a donor in a chromosome transfer event. If the other nucleus does not sustain a mortal chromosome loss, it can become a recipient in a transfer event. The chance of acquiring a chromosome lost by the donor is greater for smaller chromosomes than for larger ones and is about 0.05 for the average chromosome.