Contamination of cDNA libraries and expressed sequence-tags databases
- Frederick Cancer Research and Development Center, MD (United States)
Partially sequenced cDNAs, or expressed sequence tags (ESTs), are claimed to represent an efficient strategy for characterizing an organism`s genes. By necessity, these sequences are incompletely characterized, and examples of contamination of cDNA libraries with sequences from other species have been described. It has been suggested that a Human T-cell cDNA library (Clontech HL1963g) is contaminated by sequences from yeast (Saccharomyces cerevisiae) and an unknown bacterium. We are characterizing human ESTs that represent new members of the ATP-binding cassette transporter super-family. In examining human ESTs generated from the T-cell library, we have encountered one gene that was in fact a yeast sequence (Genbank Z15214 = SSH2 locus) and several genes that do not hybridize to human DNA or RNA. PCR primers from these sequences failed to amplify a product from human, yeast, or Escherichia coli DNA but did produce a product from a Clontech kidney cDNA library (HL1123a). To determine the source of the contamination, we amplified a conserved segment of the 16S rDNA (following a suggestion from Dr. C. Savakis) from the kidney library. The sequence of this product was nearly identical to that of the bacterium Leuconostoc lactis (300 of 304 bp). Leuconostoc species are commonly found in dairy products, fruits, vegetables, and wine and are nonpathogenic to humans. 6 refs., 1 fig.
- OSTI ID:
- 209923
- Journal Information:
- American Journal of Human Genetics, Vol. 57, Issue 5; Other Information: PBD: Nov 1995
- Country of Publication:
- United States
- Language:
- English
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