Difference between revisions of "Part:BBa K733002"

Revision as of 12:03, 24 September 2012

xylR+PxylA: A xylose inducible promoter with its transcriptional regulator.

The xylose inducible promoter used to construct this part is amplified from the integration plasmid pAX01. （Zeigler 2002）This plasmid contains a xylose inducible promoter which is originated from Bacillis megaterium. The xylose inducible promoter we constructed contains promoter pxylA which located within xylose operon, originally to drive the expression of xylA (xylose isomerase coding gene) and xylB (xylulose kinase). xylR with its promoter located at upstream of xylose operon is also included in our parts. It encodes xyl repressor which binds to xyl operator in the absence of xylose, repressing transcription event. In the presence of glucose, glucose-6-phosphate metabolized from glucose can compete with xylose in the binding site of xylose on XylR. In addition, glucose itself is also supposed to be a low efficiency inducer for XylR. (DAHL, 1997) Therefore while xylose induces the transcription, the existence of glucose, to some extent, represses gene transcription.

Sequence and Features

Assembly Compatibility:

10
COMPATIBLE WITH RFC[10]
12
COMPATIBLE WITH RFC[12]
21
INCOMPATIBLE WITH RFC[21]
Illegal XhoI site found at 847
23
COMPATIBLE WITH RFC[23]
25
COMPATIBLE WITH RFC[25]
1000
COMPATIBLE WITH RFC[1000]

Reference

Zeigler, D. (2002). Integration Vectors for Gram-Positive Bacteria (7 ed.). Columbus: The Bacillus Genetic Stock Center.

Dahl, M. K., D. Schmiedel, and W. Hillen. 1995. Glucose and glucose-6-phosphate interaction with Xyl repressor proteins from Bacillus spp. May contribute to regulation of xylose utilization. J. Bacteriol. 177:5467–5472.

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-This part is extracted by PCR from pAX01 plasmid. （Zeigler 2002）In the region of PxylA, there are two promoters with opposite directions: one regulates the expression of xylR, and another one is regulated by XylR.  (Rygus et al., 1991) When xylR is expressed, it will generate XylR, inhibiting the expression of the gene on the downstream of PxylA. However, without xylR, PxylA can be regarded as a constitutive promoter. Besides, upon the induction of xylose, the transcriptional regulator will not bind to the binding site in the promoter region, and transcription will start.
+The xylose inducible promoter used to construct this part is amplified from the integration plasmid pAX01. （Zeigler 2002）This plasmid contains a xylose inducible promoter which is originated from ''Bacillis megaterium''.
+The xylose inducible promoter we constructed contains promoter pxylA which located within xylose operon, originally to drive the expression of'' xylA'' (xylose isomerase coding gene) and'' xylB'' (xylulose kinase). ''xylR'' with its promoter located at upstream of xylose operon is also included in our parts. It encodes ''xyl'' repressor which binds to'' xyl'' operator in the absence of xylose, repressing transcription event. In the presence of glucose, glucose-6-phosphate metabolized from glucose can compete with xylose in the binding site of xylose on XylR. In addition, glucose itself is also supposed to be a low efficiency inducer for XylR. (DAHL, 1997) Therefore while xylose induces the transcription, the existence of glucose, to some extent, represses gene transcription.
 [[Image:Pxyl1.png]]  [[Image:Pxyl2.png]]
@@ Line 28: / Line 30: @@
 Zeigler, D. (2002). ''Integration Vectors for Gram-Positive Bacteria'' (7 ed.). Columbus: The Bacillus Genetic Stock Center.
-Rygus, T., Scheler, A., Allmansberger, R., & Hillen, W. (1991). Molecular cloning, structure, promoters and regulatory elements for transcription of the Bacillus megaterium encoded regulon for xylose utilization. ''Archives of Microbiology, 155,'' 535-542.
+Dahl, M. K., D. Schmiedel, and W. Hillen. 1995. Glucose and glucose-6-phosphate interaction with Xyl repressor proteins from Bacillus spp. May contribute to regulation of xylose utilization. ''J. Bacteriol.'' 177:5467–5472.