The psychrotrophic bacterium Yersinia enterocolitica requires expression of pnp, the gene for polynucleotide phosphorylase, for growth at low temperature (5°C)
The psychrotrophic bacterium Yersinia enterocolitica requires expression of pnp, the gene for polynucleotide phosphorylase, for growth at low temperature (5°C)
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DOI：
10.1046/j.1365-2958.1998.00816.x
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发表时间：
1998-05-01
影响因子：
3.6
通讯作者：
Mooi, FR
中科院分区：
文献类型：
--
作者：
Goverde, RLJ;Veld, JHJHI;Mooi, FR
嗜冷细菌小肠结肠炎耶尔森氏菌的特征在于温度依赖性适应。为了研究Y.从转座子突变体库中分离到一个在5 ℃生长受限的突变体，该突变体的转座子插入位点位于开放阅读框上游16 bp处，其预测的氨基酸序列与大肠杆菌pnp编码的核糖核酸外切酶多核苷酸磷酸化酶（PNTR）的氨基酸序列有93%的相似性。该基因的表达在PD突变体中被阻断。然而，将pnp的第二拷贝（包括其编码区上游的0.33kbp序列）引入PD突变体的染色体中恢复了pnp表达以及在5 ℃下生长的能力。此外，pnp的表达似乎是温度依赖性的：在亲本Y。在小肠结肠炎菌株中，pnp mRNA和PNp3的水平在5 ℃下比30 ℃高1.6倍。在部分二倍体重组菌株中观察到在5 ℃下类似增强的Pnp水平，这表明pnp上游的0.33 kbp区域具有冷诱导型启动子。在该区域观察到一个假定的冷休克启动子基序（ATTGG）。
The psychrotrophic bacterium Yersinia enterocolitica is characterized by temperature-dependent adaptations. To investigate Y. enterocolitica genes involved in cold adaptation, a mutant restricted in its ability to grow at 5 degrees C was isolated from a transposon mutant library, The transposon insertion site in this psychrotrophy-defective (PD) mutant mapped 16 bp upstream of an open reading frame whose predicted amino acid sequence showed 93% similarity with the Escherichia coli exoribonuclease polynucleotide phosphorylase (PNPase), encoded by pnp. Expression of this gene was blocked in the PD mutant. However, the introduction of a second copy of pnp, including 0.33 kbp sequences upstream of its coding region, into the chromosome of the PD mutant restored pnp expression as well as the ability to grow at 5 degrees C. Furthermore, the expression of pnp appeared to be temperature dependent: in the parental Y. enterocolitica strain, the levels of both pnp mRNA and PNPase were 1.6-fold higher at 5 degrees C compared with 30 degrees C. A similarly enhanced level of PNPase at 5 degrees C was observed in the merodiploid recombinant strain, which indicates that the 0.33 kbp region upstream of pnp harboured a cold-inducible promoter. A putative cold shock promoter motif (ATTGG) was observed in this region.