Fairhead C, Dujon B
Unité de Génétique Moléculaire des Levures (URA 1149 du CNRS), Institut Pasteur, Paris, France.
Yeast. 1994 Nov;10(11):1403-13. doi: 10.1002/yea.320101103.
A detailed and systematic transcript map is a first and necessary step to characterize new genes revealed by systematic sequencing. Chromosome XI of Saccharomyces cerevisiae contains 331 open reading frames (ORFs) of which 44% are of unknown function (Dujon et al., 1994). As a first study towards complete transcript analysis of chromosome XI, we have extracted RNA from three isogenic strains (a, alpha and 2n) grown in three standard laboratory media, and have analysed them using contiguous probes covering two regions of 17 and 19 kilobases, respectively. All 20 predicted ORFs in the sequences correspond to expressed genes, six of which have no predicted function. Four short ORFs which were suspected as not being real genes on the basis of their sequence are not expressed in our growth conditions. An additional transcript which does not correspond to a large ORF was found. Steady-state RNA level of most ORFs is 10 to 100 times than that of the actin gene, only three are transcribed in comparable amounts. Three ORFs show variable levels of transcripts in the different growth conditions, all patterns being different from one another. Extrapolation of these results to systematic transcript analysis of chromosome XI and other yeast chromosomes is presented.
一份详细且系统的转录图谱是表征系统测序所揭示的新基因的首要且必要步骤。酿酒酵母的第十一条染色体包含331个开放阅读框（ORF），其中44%的功能未知（迪琼等人，1994年）。作为对第十一条染色体进行完整转录分析的初步研究，我们从在三种标准实验室培养基中生长的三个同基因菌株（a、α和2n）中提取了RNA，并使用分别覆盖17和19千碱基两个区域的连续探针进行了分析。序列中的所有20个预测ORF都对应于已表达的基因，其中六个没有预测功能。基于序列怀疑不是真正基因的四个短ORF在我们的生长条件下未表达。发现了一个不对应于大ORF的额外转录本。大多数ORF的稳态RNA水平是肌动蛋白基因的10到100倍，只有三个转录量相当。三个ORF在不同生长条件下显示出不同水平的转录本，所有模式彼此不同。本文展示了将这些结果外推至第十一条染色体和其他酵母染色体的系统转录分析的情况。
