Functional expression of novel human and murine AKR1B genes

• Published in: Chemico-biological interactions Vol. 191; no. 1; pp. 177 - 184
• Main Authors: Salabei, Joshua K., Li, Xiao-Ping, Petrash, J. Mark, Bhatnagar, Aruni, Barski, Oleg A.
• Format: Journal Article
• Language: English
• Published: Ireland Elsevier Ireland Ltd 30-05-2011
• Subjects: AKR1B15; Akr1b16; Aldehyde; aldehydes; Aldo Keto Reductase; Amino Acid Sequence; Animals; bacteria; Bacteria - cytology; Cercopithecus aethiops; Cloning, Molecular; complementary DNA; COS Cells; enzyme activity; enzymes; eyes; Gene expression; Gene Expression Regulation, Enzymologic; genes; Genetic Loci - genetics; Genome, Human - genetics; heart; Humans; ketones; loci; messenger RNA; Mice; Molecular Sequence Data; open reading frames; Oxidoreductases Acting on Aldehyde or Oxo Group Donors - chemistry; Oxidoreductases Acting on Aldehyde or Oxo Group Donors - genetics; Oxidoreductases Acting on Aldehyde or Oxo Group Donors - metabolism; proteins; RNA, Messenger - genetics; RNA, Messenger - metabolism; RT-PCR; sequence analysis; spleen; testes; Aldo Keto Reductase; Gene expression; Aldehyde; AKR1B15; RT-PCR; Akr1b16
• ISSN: 0009-2797; 1872-7786
• DOI: 10.1016/j.cbi.2011.01.020

The Aldo Keto Reductases (AKRs) are a superfamily of enzymes that catalyze the reduction of biogenic and xenobiotic aldehydes and ketones. AKR1B family has 2 known members in humans and 3 in rodents. Two novel gene loci, hereafter referred to as
AKR1B15 in human and
Akr1b16 in mouse have been predicted to exist within the AKR1B clusters.
AKR1B15 displays 91% and 67% sequence identity with human genes
AKR1B10 and
AKR1B1, respectively while
Akr1b16 shares 82–84% identity with murine
Akr1b8 and
Akr1b7. We tested the hypothesis that
AKR1B15 and
Akr1b16 genes are expressed as functional proteins in human and murine tissues, respectively. Using whole tissue mRNA, we were able to clone the full-length open reading frames for
AKR1B15 from human eye and testes, and
Akr1b16 from murine spleen, demonstrating that these genes are transcriptionally active. The corresponding cDNAs were cloned into pET28a and pIRES-hrGFP-1α vectors for bacterial and mammalian expression, respectively. Both genes were expressed as 36
kDa proteins found in the insoluble fraction of bacterial cell lysate. These proteins, expressed in bacteria showed no enzymatic activity. However, lysates from COS-7 cells transfected with
AKR1B15 showed a 4.8-fold (with p-nitrobenzaldehyde) and 3.3-fold (with
dl-glyceraldehyde) increase in enzyme activity compared with untransfected COS-7 cells. The
Akr1b16 transcript was shown to be ubiquitously expressed in murine tissues. Highest levels of transcript were found in heart, spleen, and lung. From these observations we conclude that the predicted
AKR1B15 and
1b16 genes are expressed in several murine and human tissues. Further studies are required to elucidate their physiological roles.