title: Expression and localization of tissue kallikrein mRNAs in human epidermis and appendages.
abstract: Tissue kallikreins are a group of serine proteases that are found in many organs and biologic fluids. Tissue kallikrein genes (KLKs) are found on chromosome 19q13.3-4 as a gene cluster encoding 15 different serine proteases. In skin, two tissue kallikrein proteins, hK5 and hK7, are expressed in the stratum corneum and are known to be involved in desquamation of corneocytes. The possible involvement of other kallikrein proteins has not been clarified, however, nor has the significance of each member in the serine protease activity of skin been delineated. In the study described here, we examined expression and localization of KLK mRNA in normal human skin by means of RT-PCR and in situ hybridization. Quantitative RT-PCR analysis showed abundant expression of KLK1 and KLK11 mRNA, moderate expression of KLK4, KLK5, KLK6, KLK7, and KLK13 mRNA, and low expression of KLK8 mRNA in normal human skin. For KLK4, KLK8, and KLK13 mRNA, splice variants were identified to be their major mRNA species. Two variants for KLK13 mRNA were novel. The amount of the serine protease inhibitor Kazal-type 5 (SPINK5) mRNA was comparable to KLK1 and KLK11 mRNA. In situ hybridization revealed intense expression of all KLK mRNA studied except KLK12 mRNA in the stratum granulosum of normal epidermis, where SPINK5 mRNA coexisted. Excluding KLK13 mRNA, they are also expressed in hair sheath, eccrine sweat glands, and sebaceous glands. Coexpression of various KLK and SPINK5 mRNA suggests that their proteins are the candidates to balance and maintain serine protease activities in both the skin and appendages.
authors.affiliation: Department of Dermatology, Graduate School of Medical Science, School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-8641, Japan. kkomatu216@hotmail.com
authors.forename: Nahoko
authors.initials: N
authors.lastname: Komatsu
authors.forename: Minoru
authors.initials: M
authors.lastname: Takata
authors.forename: Norio
authors.initials: N
authors.lastname: Otsuki
authors.forename: Tadashi
authors.initials: T
authors.lastname: Toyama
authors.forename: Rie
authors.initials: R
authors.lastname: Ohka
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Takehara
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Saijoh
mesh_terms: D017398:Alternative Splicing; D002352:Carrier Proteins; D002478:Cells, Cultured; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology*; D015870:Gene Expression; D006801:Humans; D007610:Kallikreins / Q000235:genetics; D015603:Keratinocytes / Q000166:cytology / Q000502:physiology*; D053491:Proteinase Inhibitory Proteins, Secretory; D012333:RNA, Messenger / Q000032:analysis; D012697:Serine Endopeptidases / Q000235:genetics; D000074163:Serine Peptidase Inhibitor Kazal-Type 5; D015842:Serine Proteinase Inhibitors / Q000235:genetics; D012871:Skin Diseases / Q000503:physiopathology; D020840:Tissue Kallikreins / Q000235:genetics*
chemical_list: D002352:Carrier Proteins; D053491:Proteinase Inhibitory Proteins, Secretory; D012333:RNA, Messenger; C120650:SPINK5 protein, human; D000074163:Serine Peptidase Inhibitor Kazal-Type 5; D015842:Serine Proteinase Inhibitors; C470778:KLK13 protein, human; C425336:KLK14 protein, human; C103551:KLK6 protein, human; C082472:KLK7 protein, human; C094799:KLK8 protein, human; D007610:Kallikreins; D012697:Serine Endopeptidases; C120801:kallikrein 4; D020840:Tissue Kallikreins