Molecular cloning and sequencing of rabbit presenilin-1 cDNA fragment

Molecular cloning and sequencing of a cDNA encoding rabbit presenilin-1 (Ps1) fragment was performed by reverse transcription polymerase chain reaction (RT-PCR) using primers: 5'-GGA TGA GCA GCT AAT CTA TAC C-3' and 5'-TCC ATT CAG GGA GGT ACT TGA TA-3'. The cDNA fragment revealed 402 nucleotides. The sequence was well conserved and found to be 91, 90, 88, 87 and 78% homologous to that of human, lemur, rat, mouse and chicken, respectively. The cDNA translated into a 130 amino-acid protein fragment. The deduced amino-acid sequence was also well conserved in various species and exhibited 98% similarities with those of rat, lemur and human homologues. However, differences were noticed at residues 145, 168 and 212. This cDNA fragment is quite significant because it is the most conserved portion of Ps1 in various animals and encodes four transmembrane regions (TM2, 3, 4, 5) as defined in human Ps1. Moreover, it includes more than 50% of the sites at which substitutions have been reported in familial Alzheimer's disease (FAD). Therefore, it is suggested that the rabbit can be used as an experimental model for future studies on Ps1 and its physiological functions to work out possible pathways leading to FAD linked neurodegeneration.