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Molecular cloning and sequence analysis of adult chicken betal globin cDNA.

The molecular cloning and nucleotide sequence analysis of adult chicken beta globin mRNA is reported. DNA sequences derived from in vitro transcrption of globin mRNA were purified and amplified as recombinant DNA using the plasmid pBR322. Sequence analysis of several clones coding for beta globin strongly suggests that transcription errors may be generated near the 5' end of transcripts in vitro by reverse transcription. The complete sequence of the longest beta globin insert containing 51 bases of the 5' untranslated region as well as the complete coding and 3' untranslated regions has been determined.

Amino Acid Sequence

The organization of a nuclear DNA sequence from a higher plant: molecular cloning and characterization of soybean ribosomal DNA.

The recombinant DNA vector, lambda Charon 4A, was used to construct a library of DNA sequences from the genomic DNA of soybean (Glycine max). To define the organization of ribosomal DNA (rDNA) in the soybean genome, clones containing sequences complementary to both 17S and 25S rRNA have been isolated from this library and used in conjunction with Southern blot hybridization. The rRNA genes are tandemly reiterated with a relatively small unit repeat length of 7.8 kb. There is no heterogeneity in the length of the rDNA repeat units although they display limited differences in either base sequence or pattern of methylation. The cloned rDNA sequences are shown to comprise the entire repeat unit and have been used to obtain a detailed restriction map as well as an approximate transcription map of soybean rRNA genes. The cloning of rDNA from soybean suggests that recombinant DNA techniques can be successfully applied to the genomic DNA of higher plants despite the high degree of methylation exhibited by plant DNA.

Bacteriophage lambda

Molecular cloning of Moloney murine sarcoma virus: arrangement of virus-related sequences within the normal mouse genome.

The unintegrated circular DNA form of Moloney murine sarcoma virus (MSV) has been cloned in bacteriophage lambda. Discrete deletions in the viral genome were shown to occur during propagation of recombinant phage in Escherichia coli. Heteroduplex and restriction enzyme analyses indicated the deletion of tandemly repeated sequences within certain of the cloned MSV DNA inserts. Cloned MSV DNA was used to prepare a probe composed of its acquired cellular (src) sequences, shown previously to be necessary for MSV transformation. Analysis of EcoRI digests of normal mouse cellular DNA revealed the presence of a single 14-kilobase-pair fragment containing these sequences which lacked contiguity with endogenous type C helper viral information of the same cells. Thus, the sarcoma virus-specific sequences of MSV are represented within the normal mouse genome in a manner analogous to that of a cellular gene.

Animals

Molecular cloning of three major sequence species from Rainbow trout protamine mRNA.

Double stranded cDNA molecules complementary to purified Rainbow trout protamine mRNA have been cloned in the bacterial plasmid pBR322. In order to circumvent the problems associated with a heterogeneous cDNA probe when identifying recombinants, a comparative hybridisation technique was used which can resolve between closely related cloned sequences. Using this technique, selected recombinants were shown to carry sequences corresponding to separate major fractions of protamine mRNA. Partial nucleotide sequences of the inserts in two clones confirms this conclusion.

Animals

Purification of the mRNA for chicken very low density lipoproteinII and molecular cloning of its full-length double-stranded cDNA.

The mRNA coding for the small apo-Very Low Density Lipoprotein (apo-VLDLII) from chicken serum was highly enriched by oligo(dT) chromatography and preparative gel electrophoresis of estrogenised liver RNA. Double-stranded cDNA was synthesised by the subsequent actions of reverse transcriptase and DNA polymerase, and used for a preliminary characterisation of the structural gene. Molecular cloning of dC-tailed ds-cDNA into the Pst I site of plasmid pBR 322 yielded several recombinant clones. Five chimeric DNAs were selected and characterised by restriction enzyme mapping and electron microscopy of R-loops. At least two of them (pVLDLII 3.33 and pVLDLII 4.82) contain an almost full-length ds-transcript of VLDLII mRNA in which no more than 10-20 bases at the 5'- end are missing.

Animals

Use of phage immunity in molecular cloning experiments.

Immunity to phage superinfection is a useful selective marker in molecular cloning experiments. Plasmids which have unique sites for several different restriction endonucleases and which specify immunity to bacteriophage are described.

Chromosome Mapping

Molecular Cloning and Reverse Genetics.

This chapter describes a detailed molecular biology protocol for introducing specific point mutations into the chikungunya virus (CHIKV) genome using a reverse genetics strategy. The method utilizes an overlapping PCR-based approach to generate a mutated DNA fragment, which is then cloned into a pre-engineered CHIKV infectious clone plasmid. The protocol covers all major steps, from the initial PCRs to create the mutated insert to its digestion and ligation into the vector. It also includes procedures for bacterial transformation, colony screening via PCR and Sanger sequencing to confirm the mutation, and plasmid purification via miniprep. The document is structured with a clear introduction, a list of all required reagents and equipment, and a step-by-step methods section.

Cloning, Molecular

New mini-ColE1 as a molecular cloning vehicle.

A new mini-ColE1 plasmid, designated pAC105, was isolated. It has a molecular weight of 1.6 X 10(6) and carries information for its self-replication as well as information for conferring colicin E1 immunity upon its host. Furthermore, pAC105 undergoes replication in the presence of chloramphenicol even when a foreign deoxyribonucleic acid (pSC101) is inserted into its single EcoRI restriction site. Studies in minicell-producing strains demonstrate that pAC105 codes for only two or three polypeptides of low molecular weight. The advantages of using it as a molecular cloning vehicle are discussed.

Bacterial Proteins

The ovalbumin split gene: molecular cloning of Eco RI fragments "c" and "d".

The Eco RI fragments "c" and "d" of the ovalbumin gene (1, 2) have been isolated by molecular cloning. Restriction enzyme mapping and electron microscopy have confirmed that the two fragments contain the same ovalbumin mRNA coding sequences. These sequences are split into two regions which have been mapped in fragments "c" and "d". There is no evidence that the ovalbumin mRNA sequences contained in these fragments could be further interrupted. Our results confirm that the presence of Eco RI fragment "d" in some chickens is due to the existence of an allelic variant of the ovalbumin gene which contains an additional Eco RI site within the region corresponding to Eco RI fragment "c". This additional Eco RI site appears to be the main difference between the two alleles. Finally, our results provide a direct demonstration that most of the ovalbumin mRNA sequences are encoded for by Eco RI fragments "a", "b" and "c".

Coliphages