Molecular cloning and characterization of a putative OGG_N domain from the camel, Camelus dromedarius

Abstract

Reactive oxygen species (ROS) oxidize the guanine base in the DNA to 8-oxoguanine (8-oxoG). This lesion, if left unrepaired, causes the transversion of G:C pair to T:A following replication. 8-oxoG is targeted by one of the DNA glycosylases, namely OGG1. Arabian camel (one humped camel, Camelus dromedarius) is adapted to live in desert climate conditions under direct exposure to endogenous and exogenous ROS-producing conditions, among of them the sunlight. In the recent study, partial sequence of camel OGG-1 gene was cloned and analyzed for the first time. A DNA fragment of 567 bases was amplified by reverse transcription PCR. It is equivalent to about 55% from the coding region of the known transcript of many organisms. The level of expression of OGG-1 in different camel tissues (liver, kidney, spleen, lung and testis) was examined using real time-PCR. The highest level of OGG-1 transcript was found in the camel liver (represented as 100%) followed by testis (85%), spleen (78%), kidney (37%) and lung (3%) using 18S ribosomal subunit as endogenous control. The obtained cDNA sequence of OGG-1 showed high similarity with Ailuropoda melanoleuca (86%), Sus scrofa (86%), Canis familiaris (85%), Bos taurus (85%), Macaca mulatta (85%), Homo sapiens (84%), Pan troglodytes (84%) and Pongo abelii (82%).

Keywords: Camelus dromedarius, cloning, OGG1, gene expression, DNA glycosylase