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Biomedical subjects

E Mosharrafa

Publications and source records attributed to E Mosharrafa.

4 recordsLinked to original sources
PubMed1979

In vitro synthesis of infectious transforming DNA by the avian sarcoma virus reverse transcriptase.

Infectious DNA molecules, capable of transforming chicken embryo fibroblasts, can be synthesized by the Rous sarcoma virus-associated reverse transcriptase in vitro. The optimal enzymatic conditions employed for infectious DNA synthesis also facilitate maximum synthesis of genome length DNA. Analysis of the DNA product synthesized by detergent-disrupted Rous sarcoma virus under these conditions indicates that DNA complementary to viral RNA (minus-strand DNA) is genome length in size, whereas DNA complementary to genome length minus-strand DNA (plus-strand DNA) appears as subgenomic-length molecules ranging between 300 and 3,500 nucleotides in length. These features of the DNA product synthesized by the Rous sarcoma virus reverse transcriptase in vitro are similar to those identified in the cytoplasm of cells shortly after infection and lend credence to studies of the mechanism of reverse transcription in vitro and their significance to proviral DNA synthesis in vivo.

Avian Sarcoma Viruses↗
PubMed1977

Insertion sequence IS2 associated with int-constitutive mutants of bacteriophage lambda.

We have examined mutations in bacteriophage lambda called int-c, which confer elevated constitutive expression on the int gene for prophage integration. One class of mutations, which map between the b538 and bio386 endpoints, does not appear to be associated with any major chromosomal modification, whereas the second class has the IS2 insertion sequence in orientation II within the region between gene int and the b538 endpoint, All int-c mutations are within gene xis, with the possible exception of int-c548, which might be located between int and xis. The present data are most consistent with the following notion: (1) the point mutations of class one inactivate the tI terminator signal of the pI-tI leader RNA for gene int and thus render int expression independent of the antiterminating action of the cII and cIII products, and (2) the second class of int-c mutants is constitutive for Int because the IS2 insertion, when strategically located between int and tI, provides a new constitutive promoter for int transciption.

Coliphages↗
PubMed1976

Insertion sequence IS2 near the gene for prophage lambda excision.

In this study we characterize a variant of the lambdacI857S7 prophage, designated lambdabi2cI857S7, which carries a DNA insertion. The insertion sequence is IS2, and it resides in the antipolar orientation II just upstream from the gene for prophage excision (xis) at 61.6%lambda. This bi2 insertion mutant could prove valuable for studies on possible recombination functions of IS2 DNA and of its effect on the lambda integration and excision functions.

Chromosome Mapping↗