Streptomyces griseus의 형태분화시 85 kDa의 Penicillin-Binding Protein C를 암호화하는 pbpC 유전자의 발현 = Differential Expression of pbpC Encoding the Sporulation-specific 85 kDa Penicillin-Binding Protein during Morphological Differentiation in Streptomyces griseus

다국어 초록 (Multilingual Abstract)

Six penicillin-binding proteins (PBPs) have been detected from membrane fractions of Streptomyces griseus when fluorescein-tagged β-lactam antibiotics are used to visualize penicillin-binding proteins. An 85 kDa PBP that preferentially binds to Flu-ACA accumulates during submerged sporulation. To understand the regulation of the septation machinery during sporulation in S. griseus, we investigated the expression of the pbpC gene. The 85 kDa PBP was prevented from binding to Flu-ACA by cefoxitin that inhibits sporulation septum formation. The pbpC-disrupted strain which did not accumulate the PBP was not defective in sporulation septation, implying that another sporulation septum-specific PBP is present in S. griseus. Computer analyses revealed the pbpC gene was clustered within developmental genes mreB, mreC, mreD (murein formation genes) and sfr (member of SpoVE/FtsW/RodA family) identified in other Streptomyces. S1 nuclease protection assays revealed that four pbpC transcripts were present during submerged sporulation, but not during vegetative growth. The transcripts reached a maximum at 16 hr of sporulation in the wild-type strain and accumulated much earlier and more abundantly in a group of nonsporulating mutants, adpA and bldA that prematurely form their sporulation septa from vegetative mycelia. These observations indicated that the pbpC gene encoding the 85 kDa PBP plays a role in forming sporulation septa.

목차 (Table of Contents)

• Ⅰ. INTRODUCTION 1
• Ⅱ. MATERIAL AND METHODS 8
• 1. Bacterial Strains and Plasmids. 8
• 2. Media and Culture Conditions. 8
• 3. DNA Labeling. 12
• 4. Southern Hybridization. 16
• 5. Cloning and Characterization of the pbpC gene. 16
• 6. RNA Isolation. 16
• 7. High Resolution S1 nuclease Protection Assay. 17
• 8. Construction of Recombinant PbpC Protein. 18
• Ⅲ. RESULTS 20
• 1. Cloning and Nucleotide Sequence of the pbpC Locus 20
• 2. Transcription of pbpC in the Wild-type Strain of S. griseus. 28
• 3. Transcription of pbpC in the Class Ⅲ Nonsporulating Mutants of
• S. griseus. 31
• 4. Expression of Recombinant PbpC Protein. 33
• Ⅳ. DISCUSSION 35
• REFERENCE 37