Tag Content
SG ID
SG00008581 
UniProt Accession
Theoretical PI
8.26  
Molecular Weight
16288 Da  
Genbank Nucleotide ID
Genbank Protein ID
Gene Name
Cst8 
Gene Synonyms/Alias
Cres 
Protein Name
Cystatin-8 
Protein Synonyms/Alias
Cystatin-related epididymal spermatogenic protein; Cystatin-related epididymal-specific protein;Flags: Precursor 
Organism
Mus musculus (Mouse) 
NCBI Taxonomy ID
10090 
Chromosome Location
chr:2;148624521-148631331;1
View in Ensembl genome browser  
Function in Stage
Uncertain 
Function in Cell Type
Uncertain 
Probability (GAS) of Function in Spermatogenesis
0.664968425 
The probability was calculated by GAS algorithm, ranging from 0 to 1. The closer it is to 1, the more possibly it functions in spermatogenesis.
Description
Temporarily unavailable 
Abstract of related literatures
1. The cystatin superfamily of cysteine protease inhibitors consists of three major families, including the stefins, cystatins and kininogens. However, the recent identification of several genes that possess sequence similarity with the cystatins but have different gene or protein structures indicates that several new cystatin families or subgroups of families might exist. We previously identified the cystatin-related epididymal spermatogenic (Cres) gene, which is related to the family 2 cystatins but exhibits highly tissue-specific expression in the reproductive tract. In the studies presented here, an analysis of gene structure as well as chromosomal mapping studies suggest that the Cres gene might represent a new subgroup within the family 2 cystatins. Although the Cres gene possesses an additional exon encoding 5' untranslated sequences, its coding exons are similar in size to the three coding exons of the cystatin family 2 genes, and the Cres exon/intron splice junctions occur in identical locations as in the cystatin C gene. Furthermore, chromosomal mapping studies show that the Cres gene co-segregates with the cystatin C gene on mouse chromosome 2. Similar to the cystatin family 2 proteins, the Cres protein possesses the type A and B disulphide loops that are necessary for cystatin folding. Interestingly, Cres protein also possesses half of a type C disulphide loop. Although probably related to the cystatin genes, the Cres gene is distinct in that its promoter contains consensus motifs typical of regulated genes. Finally, reverse transcriptase-mediated PCR studies and the identification of new Cres cDNA clones indicate that the Cres mRNA is alternatively spliced, resulting in two Cres mRNAs that might be involved in the regulation of Cres function. PMID: [10229662] 

2. This study describes comprehensive polling of transcription start and termination sites and analysis of previously unidentified full-length complementary DNAs derived from the mouse genome. We identify the 5' and 3' boundaries of 181,047 transcripts with extensive variation in transcripts arising from alternative promoter usage, splicing, and polyadenylation. There are 16,247 new mouse protein-coding transcripts, including 5154 encoding previously unidentified proteins. Genomic mapping of the transcriptome reveals transcriptional forests, with overlapping transcription on both strands, separated by deserts in which few transcripts are observed. The data provide a comprehensive platform for the comparative analysis of mammalian transcriptional regulation in differentiation and development. PMID: [16141072] 

3. The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline. PMID: [15489334] 

4. As a result of examining regional-specific gene expression in the mouse epididymis, a novel cystatin-related epididymal specific (CRES) gene was identified. Substantial homology between the CRES gene and members of the cystatin family of cysteine proteinase inhibitors was observed at the amino acid level. This homology included the presence of four highly conserved cysteine residues in exact alignment with the cystatins as well as other regions of sequence characteristic of the cystatins. However, unlike the cystatins, the CRES gene does not contain specific highly conserved sequence motifs thought to be necessary for cysteine proteinase inhibitory activity. Also, in contrast to the ubiquitous expression of the cystatin C gene, Northern blot analysis and in situ hybridization demonstrated that the CRES gene is very restricted in its expression. The 0.75-kilobase CRES transcript is dramatically restricted to the very proximal caput region of the epididymis with 15- to 20-fold less expression in the testis and no expression detected in any of the other 24 tissues examined. In addition, the CRES transcript disappears 2-3 weeks after castration, suggesting a dependence on androgens. However, its expression remained undetectable even after the administration of testosterone or dihydrotestosterone. Unilateral castration also resulted in the disappearance of the CRES mRNA from the castrate epididymis, but not from the intact epididymis, suggesting that testicular factors or hormones other than androgens may be involved in the regulation of CRES gene expression. Therefore, the unique sequence of the CRES gene as well as its highly restricted expression and unusual regulation by the testis suggests that it has a very specialized role in the epididymis. PMID: [1280328] 

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Function
Performs a specialized role during sperm development andmaturation. 
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Subcellular Location
Secreted. 
Tissue Specificity
Proximal caput region of the epididymis. Lowerexpression in the testis. Within the testis it is localized to theelongating spermatids, whereas within the epididymis it isexclusively synthesized by the proximal caput epithelium. 
Gene Ontology
GO IDGO termEvidence
GO:0009986 C:cell surface IDA:MGI.
GO:0005737 C:cytoplasm IDA:MGI.
GO:0005576 C:extracellular region IDA:MGI.
GO:0004869 F:cysteine-type endopeptidase inhibitor activity IEA:UniProtKB-KW.
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Interpro
IPR000010;    Prot_inh_cystat.
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Pfam
PF00031;    Cystatin;    1.
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SMART
SM00043;    CY;    1.
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PROSITE
PRINTS
Created Date
18-Oct-2012 
Record Type
GAS predicted 
Sequence Annotation
SIGNAL        1     19       Potential.
CHAIN        20    142       Cystatin-8.
                             /FTId=PRO_0000006654.
MOTIF        77     81       Secondary area of contact (Potential).
CARBOHYD     39     39       N-linked (GlcNAc...) (Potential).
CARBOHYD    100    100       N-linked (GlcNAc...) (Potential).
DISULFID     95    105       By similarity.
DISULFID    119    139       By similarity.
CONFLICT      4     15       PLWLSLILFIIP -> GTRDEQVGESQK (in Ref. 4;
                             AAC35390).
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Nucleotide Sequence
Length: 8303 bp   Go to nucleotide: FASTA
Protein Sequence
Length: 142 bp   Go to amino acid: FASTA
The verified Protein-Protein interaction information
UniProt
Gene Symbol Ref Databases
Other Protein-Protein interaction resources
String database  
View Microarray data
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