Cloning of the cDNA for human 12-lipoxygenase.

Abstract

A full-length cDNA done encoding 12-lipoxygenase (arachidonate:oxygen 12-oxidoreductase, EC 1.13.11.31) was isolated from a human platelet cDNA library by using a cDNA for human reticulocyte 15-lipoxygenase as probe for the initial screening. The cDNA had an open reading frame encoding 662 amino acid residues with a calculated molecular weight of 75,590. Three independent clones revealed minor heterogeneities in their DNA sequences. Thus, in three positions of the deduced amino acid sequence, there is a choice between two different amino acids. The deduced sequence from the clone plT3 showed 65% identity with human reticulocyte 15-lipoxygenase and 42% identity with human leukocyte 5-lipoxygenase. The 12-lipoxygenase cDNA recognized a 3.0-kilobase mRNA species in platelets and human erythroleukemia cells (HEL cells). Phorbol 12-tetradecanoyl 13-acetate induced megakaryocytic differentiation of HEL cells and 12-lipoxygenase activity and increased mRNA for 12-lipoxygenase. The identity of the cloned 12-lipoxygenase was assured by expression in a mammalian cell line (COS cells). Human platelet 12-lipoxygenase has been difficult to purify to homogeneity. The cloning of this cDNA will increase the possibilities to elucidate the structure and function of this enzyme.

Thematic Review Series: Proteomics. An integrated omics analysis of eicosanoid biology

“…The human enzyme was concurrently cloned by Funk, Furci, and FitzGerald (140) and Isumi et al (141) in 1990, and due to its high level of expression in these cells has been termed platelet-type 12-lipoxygenase (12-LOX-p). However, itʼs also abundant in epithelial tissue, and has been demonstrated to provide human skin melanomas with survival signals and promote tumor metastasis (142)(143)(144).…”

Potential involvement of the AML1-MTG8 fusion protein in the granulocytic maturation characteristic of the t(8;21) acute myelogenous leukemia revealed by microarray analysis

“…58 Arachidonate 12-lipoxiganase, encoded by Alox12, is a member of the lipoxygenase family and is expressed in platelets, megakaryocytes, epidermal cells, and some tumor cell lines. [60][61][62][63] Overexpression of arachidonate 12-lipoxiganase in the human breast cancer cell line MCF-7 and the human prostate adenocarcinoma cell line PC3 stimulates tumor growth by inducing angiogenic activity. 64,65 At present, we have not determined if the expression of these genes is affected in leukemic cells.…”

Functional interaction between c-Jun and promoter factor Sp1 in epidermal growth factor-induced gene expression of human 12( S )-lipoxygenase

“…It catalyzes the transformation of arachidonic acid into 12(S)-hydroperoxyeicosatetraenoic acid and is converted subsequently to 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE] by a glutathione-dependent peroxidase (2). Human platelet-type 12(S)-lipoxygenase was also found in human erythroleukemia cells (3,4), epidermal cells (5), and epidermoid carcinoma A431 cells (6). 12(S)-HETE may play a significant role in the pathogenesis of some epidermal and epithelial inflammation, because a markedly elevated 12(S)-HETE level was found in psoriatic plague (7).…”