Chromosomal walking of flanking regions from short known sequences in GC-rich plant genomic DNA

2003 ◽  
Vol 21 (3) ◽  
pp. 295-302 ◽  
Author(s):  
An Michiels ◽  
Mark Tucker ◽  
Wim van den Ende ◽  
Andre Van Laere
Author(s):  
Kuldeepsingh A. Kalariya ◽  
Ram Prasnna Meena ◽  
Lipi Poojara ◽  
Deepa Shahi ◽  
Sandip Patel

Abstract Background Squalene synthase (SQS) is a rate-limiting enzyme necessary to produce pentacyclic triterpenes in plants. It is an important enzyme producing squalene molecules required to run steroidal and triterpenoid biosynthesis pathways working in competitive inhibition mode. Reports are available on information pertaining to SQS gene in several plants, but detailed information on SQS gene in Gymnema sylvestre R. Br. is not available. G. sylvestre is a priceless rare vine of central eco-region known for its medicinally important triterpenoids. Our work aims to characterize the GS-SQS gene in this high-value medicinal plant. Results Coding DNA sequences (CDS) with 1245 bp length representing GS-SQS gene predicted from transcriptome data in G. sylvestre was used for further characterization. The SWISS protein structure modeled for the GS-SQS amino acid sequence data had MolProbity Score of 1.44 and the Clash Score 3.86. The quality estimates and statistical score of Ramachandran plots analysis indicated that the homology model was reliable. For full-length amplification of the gene, primers designed from flanking regions of CDS encoding GS-SQS were used to get amplification against genomic DNA as template which resulted in approximately 6.2-kb sized single-band product. The sequencing of this product through NGS was carried out generating 2.32 Gb data and 3347 number of scaffolds with N50 value of 457 bp. These scaffolds were compared to identify similarity with other SQS genes as well as the GS-SQSs of the transcriptome. Scaffold_3347 representing the GS-SQS gene harbored two introns of 101 and 164 bp size. Both these intronic regions were validated by primers designed from adjoining outside regions of the introns on the scaffold representing GS-SQS gene. The amplification took place when the template was genomic DNA and failed when the template was cDNA confirmed the presence of two introns in GS-SQS gene in Gymnema sylvestre R. Br. Conclusion This study shows GS-SQS gene was very closely related to Coffea arabica and Gardenia jasminoides and this gene harbored two introns of 101 and 164 bp size.


1999 ◽  
Vol 181 (10) ◽  
pp. 3155-3163 ◽  
Author(s):  
M. Gita Bangera ◽  
Linda S. Thomashow

The polyketide metabolite 2,4-diacetylphloroglucinol (2,4-DAPG) is produced by many strains of fluorescent Pseudomonas spp. with biocontrol activity against soilborne fungal plant pathogens. Genes required for 2,4-DAPG synthesis by P. fluorescensQ2-87 are encoded by a 6.5-kb fragment of genomic DNA that can transfer production of 2,4-DAPG to 2,4-DAPG-nonproducing recipientPseudomonas strains. In this study the nucleotide sequence was determined for the 6.5-kb fragment and flanking regions of genomic DNA from strain Q2-87. Six open reading frames were identified, four of which (phlACBD) comprise an operon that includes a set of three genes (phlACB) conserved between eubacteria and archaebacteria and a gene (phlD) encoding a polyketide synthase with homology to chalcone and stilbene synthases from plants. The biosynthetic operon is flanked on either side by phlEand phlF, which code respectively for putative efflux and regulatory (repressor) proteins. Expression in Escherichia coli of phlA, phlC, phlB, andphlD, individually or in combination, identified a novel polyketide biosynthetic pathway in which PhlD is responsible for the production of monoacetylphloroglucinol (MAPG). PhlA, PhlC, and PhlB are necessary to convert MAPG to 2,4-DAPG, and they also may function in the synthesis of MAPG.


1986 ◽  
Vol 6 (2) ◽  
pp. 593-600
Author(s):  
J E Linz ◽  
C Katayama ◽  
P S Sypherd

We cloned three genes from Mucor racemosus coding for protein synthesis elongation factor 1 alpha (EF-1 alpha). A 110-base-pair (bp) EF-1 alpha-specific cDNA clone was identified by hybrid-selected translation. The nucleotide sequence of the cDNA showed significant homology to a region of the Saccharomyces cerevisiae genes for EF-1 alpha (TEF1 and TEF2). The cDNA was used to isolate an 850-bp EcoRI genomic DNA fragment containing a portion of the EF-1 alpha gene. Screening of a lambda/M. racemosus genomic DNA bank with the 850-bp EcoRI probe resulted in the identification of three DNA fragments containing a common 850-bp EcoRI fragment within a short overlapping region. S1 nuclease analysis of the three EF-1 alpha DNA fragments showed that the EF-1 alpha transcript covered the short overlapping region in the clones. Restriction fragments purified from flanking regions in each clone were used to probe a HindIII digest of M. racemosus genomic DNA. Each flanking probe hybridized to one of three DNA fragments which hybridized to the 850-bp EF-1 alpha-specific probe. Nucleotide sequence data from two random "shotgun clones" of one of the three genes show good homology to two regions of S. cerevisiae TEF1. The data indicate the presence of three genes for EF-1 alpha in M. racemosus located at unique sites in the genome.


1986 ◽  
Vol 6 (2) ◽  
pp. 593-600 ◽  
Author(s):  
J E Linz ◽  
C Katayama ◽  
P S Sypherd

We cloned three genes from Mucor racemosus coding for protein synthesis elongation factor 1 alpha (EF-1 alpha). A 110-base-pair (bp) EF-1 alpha-specific cDNA clone was identified by hybrid-selected translation. The nucleotide sequence of the cDNA showed significant homology to a region of the Saccharomyces cerevisiae genes for EF-1 alpha (TEF1 and TEF2). The cDNA was used to isolate an 850-bp EcoRI genomic DNA fragment containing a portion of the EF-1 alpha gene. Screening of a lambda/M. racemosus genomic DNA bank with the 850-bp EcoRI probe resulted in the identification of three DNA fragments containing a common 850-bp EcoRI fragment within a short overlapping region. S1 nuclease analysis of the three EF-1 alpha DNA fragments showed that the EF-1 alpha transcript covered the short overlapping region in the clones. Restriction fragments purified from flanking regions in each clone were used to probe a HindIII digest of M. racemosus genomic DNA. Each flanking probe hybridized to one of three DNA fragments which hybridized to the 850-bp EF-1 alpha-specific probe. Nucleotide sequence data from two random "shotgun clones" of one of the three genes show good homology to two regions of S. cerevisiae TEF1. The data indicate the presence of three genes for EF-1 alpha in M. racemosus located at unique sites in the genome.


1993 ◽  
Vol 70 (03) ◽  
pp. 500-505 ◽  
Author(s):  
B Wyler ◽  
L Daviet ◽  
H Bortkiewicz ◽  
J-C Bordet ◽  
J L McGregor

SummaryGlycoprotein CD36, also known as GPIIIb or GPIV, is a major platelet glycoprotein that bears the newly identified Naka alloantigen. The aim of this study was to clone platelet CD36 and investigate other forms of CD36-cDNA present in monocytes, endothelial and HEL cells. RNA from above mentioned cells were reverse transcribed (RT), using specific primers for CD36, and amplified by the polymerase chain reaction (PCR) technique. Sequencing the different amplified platelet derived cDNA fragments, spanning the whole coding and flanking regions, showed the near identity between platelet and CD36-placenta cDNA. Platelet CD36-cDNA cross-hybridized, in Southern blots, with RT-PCR amplified cDNA originating from monocytes, endothelial and HEL cells. However, monocytes showed a RT-PCR amplified cDNA fragment (561 bp) that was present in platelets and placenta but not on endothelial on HEL-cells. Northern blot analysis of platelet RNA hybridized with placenta CD36 indicated the presence of a major (1.95 kb) and a minor (0.95 kb) transcript. The 1.95 kb transcript was the only one observed on Northern blots of monocytes, endothelial and HEL cells. These results indicate that the structure of CD36 expressed in platelets is similar, with the exception of the 3’ flanking region, to that of placenta. Differences in apparent molecular weight between CD36 and CD36-like glycoproteins may be due to post-translational modifications.


1993 ◽  
Vol 69 (03) ◽  
pp. 217-220 ◽  
Author(s):  
Jonathan B Rosenberg ◽  
Peter J Newman ◽  
Michael W Mosesson ◽  
Marie-Claude Guillin ◽  
David L Amrani

SummaryParis I dysfibrinogenemia results in the production of a fibrinogen molecule containing a functionally abnormal γ-chain. We determined the basis of the molecular defect using polymerase chain reaction (PCR) to amplify the γ-chain region of the Paris I subject’s genomic DNA. Comparative sequence analysis of cloned PCR segments of normal and Paris I genomic DNA revealed only an A→G point mutation occurring at nucleotide position 6588 within intron 8 of the Paris I γ-chain gene. We examined six normal individuals and found only normal sequence in this region, indicating that this change is not likely to represent a normal polymorphism. This nucleotide change leads to a 45 bp fragment being inserted between exons 8 and 9 in the mature γparis I chain mRNA, and encodes a 15 amino acid insert after γ350 [M-C-G-E-A-L-P-M-L-K-D-P-C-Y]. Alternative splicing of this region from intron 8 into the mature Paris I γ-chain mRNA also results after translation into a substitution of S for G at position γ351. Biochemical studies of 14C-iodoacetamide incorporation into disulfide-reduced Paris I and normal fibrinogen corroborated the molecular biologic predictions that two additional cysteine residues exist within the γpariS I chain. We conclude that the insertion of this amino acid sequence leads to a conformationallyaltered, and dysfunctional γ-chain in Paris I fibrinogen.


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