TRANSCRIPTIONAL AND TRANSLATIONAL FEATURES OF A SPORULATION GENE OF STREPTOMYCES-GRISEUS
TRANSCRIPTIONAL AND TRANSLATIONAL FEATURES OF A SPORULATION GENE OF STREPTOMYCES-GRISEUS
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DOI：
10.1016/0378-1119(90)90413-l
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发表时间：
1990-10-30
期刊：
影响因子：
3.5
通讯作者：
KENDRICK, KE
中科院分区：
文献类型：
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作者：
BABCOCK, MJ;KENDRICK, KE
对一类灰色链霉菌突变体恢复孢子形成的2.8 kb DNA片段的核苷酸（nt）序列进行分析，发现其开放阅读框（ORF）具有编码55.5 kDa多肽的潜力。在编码序列中存在框内TTA表明翻译可能需要由bldA基因编码的tRNAUUALEu。两个重叠的转录本起始于相隔258 nt的转录起始点（tsp），并以相同的方向转录。下游tsp位于ORF内，之后是第二个潜在的翻译起始位点，其将编码与55.5-kDa多肽相同的阅读框中的49.5-kDa多肽。转录测定表明，两个tsp功能在营养生长，但相对丰度较短的转录下降，在沉水孢子形成的早期阶段。序列缺失的亚克隆分析表明，较长的ORF的表达是必要的，以补充秃突变体。两个tsp交替与潜在的翻译起始密码子的存在表明，具有相同的C末端，但不同的N末端的两个多肽的时间调节合成。
The nucleotide (nt) sequence of a 2.8-kb fragment of DNA that restores sporulation to one class of bald mutants of Streptomyces griseus revealed an open reading frame (ORF) with the potential to encode a 55.5-kDa polypeptide. The presence of an in-frame TTA in the coding sequence indicated that translation is likely to require the tRNAUUALeu encoded by the bldA gene. Two overlapping transcripts are initiated at transcriptional start points (tsp) separated by 258 nt and are transcribed in the same direction. The downstream tsp lies within the ORF and is followed by a second potential translation initiation site, which would encode a 49.5-kDa polypeptide in the same reading frame as the 55.5-kDa polypeptide. Transcription assays suggested that both tsp functioned during vegetative growth, but the relative abundance of the shorter transcript decreased during the early stages of submerged sporulation. Analysis of sequentially deleted subclones indicated that expression of the longer ORF was necessary to complement bald mutants. The presence of two tsp alternating with potential translation start codons suggests the temporally regulated synthesis of two polypeptides that have identical C termini but different N termini.