Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two members (CST4 and CST5) of the cystatin gene family have been characterized partially by DNA analysis. The CST4 clone contained the gene coding for the precursor form(141 amino acids) of cystatin S, and its exon-intron organization is the same as that of other members (the cystatin SN gene at the CST1 locus, the cystatin SA gene at the CST2 locus, the cystatin C gene at the CST3 locus and a cystatin pseudogene at the CSTP1 locus). The second cystatin pseudogene was elucidated in the clone, CST5, and it was assigned to the CSTP2 locus. Alignment of DNA sequences of cystatin genes with other genes suggested that the genes for cystatins, kininogens, and Bowman-Birk type inhibitors have evolved from an ancient ribonuclease-like gene.
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PMID:Characterization of two members (CST4 and CST5) of the cystatin gene family and molecular evolution of cystatin genes. 133 20

Type 2 cystatins comprise a class of cysteine peptidase inhibitor presumed to mediate protective functions at various locations, including the oral cavity. Seven cystatin genes are clustered within a 300-kb region of human 20p11.2. "Salivary" cystatins, encoded by CST1, 2, 4, and 5, are present in saliva at significant levels but have also been reported in other secretions, such as tears, suggesting that during their evolution, these genes have acquired mechanisms directing differential tissue-specific expression. However, their patterns of expression, which might also provide additional clues to their individual functions, have not been determined. Gene-specific RNase protection assays were used to examine the qualitative and quantitative distribution of expression of these seven genes within a collection of 23 adult human tissues. The CST3 gene, encoding cystatin C, was expressed at modest levels in all tissues examined. The presumptive pseudogenes CSTP1 and CSTP2 were not expressed at detectable levels in any tissue. The CST1, 2, 4, and 5 genes were expressed in differential, tissue-specific patterns. Expression of CST2 and CST5 was restricted to the submandibular and parotid glands, while CST1 and CST4 were expressed in these tissues and in the lacrimal gland. Immunohistochemistry studies localized expression to the serous-type secretory end pieces. Coexpression of CST1 and CST4 was also observed in the epithelial lining of the gallbladder and seminal vesicle. The CST1 product was detected in the tracheal glands and CST4 in the kidney and prostate. Despite their different adult patterns of expression, analysis of CST1, 2, 4, and 5 mRNA levels in infant submandibular glands demonstrated a coordinate upregulation of expression of between 3.5 and 9 months of age. The patterns of cystatin gene expression are consistent with several proposed oral functions of the salivary cystatins but also suggest they are important in other locations and that, despite their close sequence similarity, they are individually specialized.
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PMID:Expression of type 2 cystatin genes CST1-CST5 in adult human tissues and the developing submandibular gland. 1187 80