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BIDIRECTIONAL  GENE  SEQUENCES  WITH  SIMILAR HOMOLOGY TO FUNCTIONAL PROTEINS OF ALKANE DEGRADING BACTERIUM PSEUDOMONAS FREDRIKSBERGENSIS DNA

AHMED ABDEL-MEGEED^1,2,3

Abstract: The potential for two overlapping fragments of DNA from a clone of newly isolated alkanes degrading bacterium Pseudomonas frederiksbergensis encoding sequences with similar homology to two parts of functional proteins is described. One strand contains a sequence with high homology to alkanes monooxygenase (alkB), a member of the alkanes hydroxylase family, and the other strand contains a sequence with some homology to alcohol dehydrogenase gene (alkJ). Overlapping of the genes on opposite strands has been reported in eukaryotic species, and is now reported in a bacterial species. The sequence comparisons and ORF_S results revealed that the regulation and the genes organization involved in alkane oxidation represented in Pseudomonas frederiksberghensis varies among the different known alkane degrading bacteria. The alk gene cluster containing homologues to the known alkane monooxygenase (alkB), and rubredoxin (alkG) are oriented in the same direction, whereas alcohol dehydrogenase (alkJ) is oriented in the opposite direction. Such genomes encode messages on both strands of the DNA, or in an overlapping but different reading frames, of the same strand of DNA. The possibility of creating novel genes from pre-existing sequences, known as overprinting, which is a widespread phenomenon in small viruses. Here, the origin and evolution of the gene overlap to bacteriophages belonging to the family Microviridae have been investigated. Such a phenomenon is most widely described in extremely small genomes such as those of viruses or small plasmids, yet here is a unique phenomenon.

¹Department of Botany and Microbiology, College of Sciences, King Saud University, P.O. Box 2455 - Riyadh 11451, Kingdom of Saudi Arabia

²Faculty of Agriculture (Saba Basha), Alexandria University, Egypt.

³Abdul Rahman Al Jeraisy Chair DNA Res, Riyadh 11451, Saudi Arabia

Corresponding author E-mail: aamahmoud@ksu.edu.sa & hekemdar@yahoo.com