東華大學圖書館 |

Language: English

Help

回圖書館首頁

手機版館藏查詢

Back

Switch To: Labeled | MARC Mode | ISBD

T7-like RNA polymerases and transcri...

Chang, Ching-Chun,

Linked to FindBook

Google Book

Amazon

博客來

T7-like RNA polymerases and transcription initiation in maize organelles /

Record Type:	Electronic resources : Monograph/item
Title/Author:	T7-like RNA polymerases and transcription initiation in maize organelles // Ching-Chun Chang.
Author:	Chang, Ching-Chun,
Description:	1 electronic resource (146 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 62-07, Section: B.
Contained By:	Dissertations Abstracts International62-07B.
Subject:	Molecular biology. -
Online resource:	https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9967428
ISBN:	9780599721937

T7-like RNA polymerases and transcription initiation in maize organelles /
Chang, Ching-Chun,

T7-like RNA polymerases and transcription initiation in maize organelles /Ching-Chun Chang. - 1 electronic resource (146 pages)

Source: Dissertations Abstracts International, Volume: 62-07, Section: B.

Although mitochondrial promoters have been well defined in vascular plants, relatively little is known of the transcriptional machinery. To characterize the transcription initiation complex at the maize mitochondrial atpA promoter, exonuclease III was used to map the borders of DNA-protein interactions. These experiments revealed that with a wild-type promoter, protein factors occupy as much as 36 bp, from positions -20 to +16 relative to the transcription initiation site. As a first step to characterize the maize mitochondrial transcription machinery, we obtained two maize cDNA clones, rpoTm and rpoTp, that encode putative T7-like RNA polymerases. The predicted proteins, RpoTm and RpoTp, share 54% amino acid sequence identity, are nucleus-encoded, and are probably encoded by single copy genes. Sequence alignments, among several T7-like RNA polymerases revealed at least 11 conserved domains as well as conservation of some functional motifs and important catalytic residues; suggesting that rpoTm and rpoTp encoded functional RNA polymerase. In vivo cellular localization experiments using transient expression of the green fluorescent protein suggest that the rpoTm and rpoTp encoded proteins are targeted exclusively to mitochondria and plastids, respectively. Biochemical studies using an antibody raised against the C-terminus of RpoTp identified mitochondrial polypeptides of approximately 100 kD in a transcriptionally active fraction. Their presence was correlated with RNA polymerase activity, and the antibody inhibited mitochondrial in vitro transcription activity. Together, these results strongly suggest that the product of rpoTm is involved in maize mitochondrial transcription. Immunoblot analysis and an antibody-inked polymerase assay, together with the in vivo localization, indicated that rpoTp specifies a plastid RNA polymerase component. Although it is not clear that how many protein factors are required for specific transcription initiation in higher plant mitochondria, several observations suggested that the machinery is similar to that of yeast, which consists of two proteins. One of these proteins is a core RNA polymerase of the T7 family, while the other factor has limited sequence homology, and strong functional homology, to bacterial sigma factors. Two possible plant mitochondrial transcription factors, ZmSig2 and p63, were proposed based on their resemblance to bacterial sigma factors, and localization. In an attempt to reconstitute transcription initiation, we have overexpressed ZmSig2 and p63 in E. coli, and purified the proteins.

English

ISBN: 9780599721937Subjects--Topical Terms:

517296
Molecular biology.
Subjects--Index Terms:

Maize organelles

T7-like RNA polymerases and transcription initiation in maize organelles /
LDR:03872nmm a22003973i 4500 001 2434721
005 20250923060946.5
006 m o d
007 cr|nu||||||||
008 261011s2000 miu||||||m |||||||eng d
020 $a 9780599721937
035 $a (MiAaPQD)AAI9967428
035 $a AAI9967428
040 $a MiAaPQD $b eng $c MiAaPQD $e rda
100 1 $a Chang, Ching-Chun, $e author. $3 3824795
245 1 0 $a T7-like RNA polymerases and transcription initiation in maize organelles / $c Ching-Chun Chang.
264 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2000
300 $a 1 electronic resource (146 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 62-07, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
502 $b Ph.D. $c Cornell University $d 2000.
520 $a Although mitochondrial promoters have been well defined in vascular plants, relatively little is known of the transcriptional machinery. To characterize the transcription initiation complex at the maize mitochondrial atpA promoter, exonuclease III was used to map the borders of DNA-protein interactions. These experiments revealed that with a wild-type promoter, protein factors occupy as much as 36 bp, from positions -20 to +16 relative to the transcription initiation site. As a first step to characterize the maize mitochondrial transcription machinery, we obtained two maize cDNA clones, rpoTm and rpoTp, that encode putative T7-like RNA polymerases. The predicted proteins, RpoTm and RpoTp, share 54% amino acid sequence identity, are nucleus-encoded, and are probably encoded by single copy genes. Sequence alignments, among several T7-like RNA polymerases revealed at least 11 conserved domains as well as conservation of some functional motifs and important catalytic residues; suggesting that rpoTm and rpoTp encoded functional RNA polymerase. In vivo cellular localization experiments using transient expression of the green fluorescent protein suggest that the rpoTm and rpoTp encoded proteins are targeted exclusively to mitochondria and plastids, respectively. Biochemical studies using an antibody raised against the C-terminus of RpoTp identified mitochondrial polypeptides of approximately 100 kD in a transcriptionally active fraction. Their presence was correlated with RNA polymerase activity, and the antibody inhibited mitochondrial in vitro transcription activity. Together, these results strongly suggest that the product of rpoTm is involved in maize mitochondrial transcription. Immunoblot analysis and an antibody-inked polymerase assay, together with the in vivo localization, indicated that rpoTp specifies a plastid RNA polymerase component. Although it is not clear that how many protein factors are required for specific transcription initiation in higher plant mitochondria, several observations suggested that the machinery is similar to that of yeast, which consists of two proteins. One of these proteins is a core RNA polymerase of the T7 family, while the other factor has limited sequence homology, and strong functional homology, to bacterial sigma factors. Two possible plant mitochondrial transcription factors, ZmSig2 and p63, were proposed based on their resemblance to bacterial sigma factors, and localization. In an attempt to reconstitute transcription initiation, we have overexpressed ZmSig2 and p63 in E. coli, and purified the proteins.
546 $a English
590 $a School code: 0058
650 4 $a Molecular biology. $3 517296
650 4 $a Plant propagation. $3 1621657
650 4 $a Plant sciences. $3 3173832
653 $a Maize organelles
653 $a RNA polymerases
653 $a T7-like
653 $a Transcription initiation
690 $a 0307
690 $a 0479
710 2 $a Cornell University. $e degree granting institution. $3 3767664
773 0 $t Dissertations Abstracts International $g 62-07B.
790 $a 0058
791 $a Ph.D.
792 $a 2000
856 4 0 $u https://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9967428