{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,5]],"date-time":"2026-02-05T08:36:22Z","timestamp":1770280582617,"version":"3.49.0"},"reference-count":56,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2015,4,30]],"date-time":"2015-04-30T00:00:00Z","timestamp":1430352000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>YKL-40 (YKL for the first three N-terminal residues of a 40 kDa protein) belongs to a group of human chitinase-like proteins (CLPs), which are similar to chitinases but lack chitinolytic activity. YKL-40 mRNA and its protein levels have been reported elevated in multiple disorders including asthma, cystic fibrosis, rheumatoid arthritis and malignant tumors. Here, we quantified the YKL-40 mRNA levels and compared them with chitinases and housekeeping genes in normal human tissues. To establish the quantitative real-time PCR (qPCR) system for evaluation of relative YKL-40 mRNA levels, we constructed  a human standard DNA molecule by ligating cDNAs of YKL-40, two mammalian chitinases and two housekeeping genes in a one-to-one ratio. We generated cDNAs from various normal human tissues and analyzed the YKL-40 mRNA expression levels using a qPCR system with the standard DNA. We found that YKL-40 mRNA is present widely in human tissues while its expression patterns exhibit clear tissue specificity. Highest YKL-40 mRNA levels were detected in the liver, followed by kidney, trachea and lung. The levels of  YKL-40 mRNA in the kidney and liver were more than 100-times higher than those of chitotriosidase mRNA. Our study provides for the first time a comprehensive analysis  of the relative expression levels of YKL-40 mRNA versus mammalian chitinases in normal human tissues.<\/jats:p>","DOI":"10.3390\/ijms16059922","type":"journal-article","created":{"date-parts":[[2015,4,30]],"date-time":"2015-04-30T08:58:53Z","timestamp":1430384333000},"page":"9922-9935","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Quantitative Real-Time PCR Analysis of YKL-40 and  Its Comparison with Mammalian Chitinase mRNAs in  Normal Human Tissues Using a Single Standard DNA"],"prefix":"10.3390","volume":"16","author":[{"given":"Misa","family":"Ohno","sequence":"first","affiliation":[{"name":"Department of Chemistry and Life Science, Kogakuin University, Hachioji,  Tokyo 192-0015, Japan"},{"name":"Research Fellow of Japan Society for the Promotion of Science (DC2), Koujimachi, Chiyoda-ku, Tokyo 102-0083, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Bauer","sequence":"additional","affiliation":[{"name":"Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuta","family":"Kida","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Life Science, Kogakuin University, Hachioji,  Tokyo 192-0015, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masayoshi","family":"Sakaguchi","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Life Science, Kogakuin University, Hachioji,  Tokyo 192-0015, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yasusato","family":"Sugahara","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Life Science, Kogakuin University, Hachioji,  Tokyo 192-0015, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1095-8306","authenticated-orcid":false,"given":"Fumitaka","family":"Oyama","sequence":"additional","affiliation":[{"name":"Department of Chemistry and Life Science, Kogakuin University, Hachioji,  Tokyo 192-0015, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,4,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1988","DOI":"10.3390\/md8071988","article-title":"Chitin research revisited","volume":"8","author":"Khoushab","year":"2010","journal-title":"Mar. 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