Richard E. Gelinas

Two sequence-specific endonucleases from Moraxella bovis☆

Abstract Two new sequence-specific endodeoxyribonucleases have been partially purified from Moraxella bovis. These restriction-like enzymes, MboI and MboII, each cleave bacteriophage lambda DNA and adenovirus-2 DNA at more than 50 sites. MboI recognizes the sequence 5′ ↓ G-A-T-C 3′ 3′ C-T-A-G ↑ 5′ and cleaves at the sites indicated by the arrows. A specific endonuclease, MosI, has also been purified from Moraxella osloenis and recognizes the same sequence as MboI.

Adenovirus-2 messengers--an example of baroque molecular architecture

Adenovirus type 2 (Ad2) causes respiratory infections in humans, grows productively on human cell lines such as HeLa and KB, and can transform rat primary cell lines (Tooze 1973). The Ad2 virion consists of a linear duplex DNA chromosome 35,000 base pairs (bp) long (23 × 106 daltons) contained within an icosahedral capsid composed of at least ten different proteins. After penetration of the cell membrane, the viral DNA and several core proteins associated with it are transported to the nucleus, where early RNA transcription begins within 2 hours. About 8 hours after infection, viral DNA replication commences, reaching a maximum rate several hours later. Late transcription to produce messenger RNA (mRNA) for capsid and other virus-specific proteins begins after the onset of DNA replication and continues for about 2 days, when the infected cells die.

A specific endonuclease from Brevibacterium albidum.

Abstract A new restriction-like endonuclease, Bal I, has been partially purified from Brevibacterium albidum . This enzyme cleaves bacteriophage λ DNA at least 18 times and adenovirus-2 DNA at least 16 times, but does not cleave simian virus 40 DNA. All sites cleaved by Bal I are also cut by the specific endonuclease Hae III from Haemophilus aegyptius . The recognition sequence of Bal I is 5′-T-G-G ↓ C-C-A-3′ 3′-A-C-C ↓ G-G-T-5′ and the cleavage site is indicated by the arrows.

Determination and analysis of adenovirus-2 DNA sequences which may include signals for late messenger RNA processing.

Abstract Nucleotide sequences have been determined for regions of the adenovirus-2 genome from which the three principal leaders of late messenger RNA are transcribed. We have also sequenced the region which surrounds a fourth leader only on the fiber mRNA and the region of the genome immediately preceding the translated portion. These sequences were examined directly for repeated features and were also used to draw secondary structure models. Our study of these sequences has revealed specific repeated primary and secondary structural features at both the 5′ and 3′ ends of each of the conserved RNA segments present in adenovirus-2 late mRNA transcripts.