Isolation and characterization of Rac1 pseudogenes (psi1Rac1-psi4Rac1) in the human genome.
Ras-related C3 toxin substrate 1 (Rac1) is a small Rho-GTPase with important functions in fundamental cellular processes such as cytoskeleton rearrangements, signal transduction, cell cycle progression and malignant transformation. Using Rac1 primer, we identified a 5.5-kb DNA sequence on chromosome 4 (Chr. 4) in the human genome, containing the intronless protein coding sequence of Rac1. Sequence analysis revealed features of a processed pseudogene, which we named psi1Rac1, that could be detected by Southern blot and polymerase chain reaction (PCR) on genomic DNA. A psi1Rac1 pseudogene transcript was not detected by reverse transcription-polymerase chain reaction (RT-PCR), nor had the psi1Rac1 promoter any transcriptional activity. In addition, three other intronless pseudogenes of Rac1 on chromosomes 4, 13 and X were identified (psi1Rac1-psi4Rac1) sharing an 86-96% sequence similarity with Rac1. Neither RT-PCR with pseudogene specific restriction enzymes, nor the sequencing of 130 cDNA clones from benign and malignant breast tissue and cell lines, detected the transcription of any of the Rac1 pseudogenes (psi2Rac1-psi4Rac1). Existence of Rac1 pseudogenes should be taken into consideration when analyzing genomic alterations of the human Rac1 gene.
Department of Medicine/Division of Pulmonology and Critical Care, University of California, San Francisco, San Francisco, CA, USA.
Matthias Christian
MC
Kugler
Markus
M
Gerhard
Andreas
A
Schnelzer
Katja
K
Borzym
Richard
R
Reinhardt
Manfred
M
Schmitt
Ernst
E
Lengyel
D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D002460:Cell Line; D003001:Cloning, Molecular; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D015894:Genome, Human; D006801:Humans; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics*; D010802:Phylogeny; D011544:Pseudogenes / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D020744:rac GTP-Binding Proteins / Q000235:genetics*; D020830:rac1 GTP-Binding Protein
D009479:Neuropeptides; C107953:RAC1 protein, human; D004247:DNA; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein