NCBI Summary:
This gene encodes the A-chain polypeptide of serum complement subcomponent C1q, which associates with C1r and C1s to yield the first component of the serum complement system. C1q deficiency is associated with lupus erythematosus and glomerulonephritis. C1q is composed of 18 polypeptide chains which include 6 A-chains, 6 B-chains, and 6 C-chains. Each chain contains an N-terminal collagen-like region and a C-terminal C1q globular domain. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Nov 2016]
General function
Extracellular binding protein
Comment
Cellular localization
Secreted
Comment
Ovarian function
Cumulus expansion, Ovulation
Comment
Induced expression of pattern recognition receptors (PRRs) in cumulus oocyte complexes (COCs): Novel evidence for innate immune-like functions during ovulation. Shimada M et al. Ovulation is the complex, inflammatory-like process by which the cumulus oocyte complex (COC) is released from a mature, preovulatory (PO) follicle through a rupture site at the ovarian surface and requires expression of genes that generate and stabilize the expanded extracellular COC matrix. Gene profiling analyses of COCs at selected time intervals during ovulation revealed that many genes associated with immune related surveillance functions were also induced in cumulus cells. Specifically, cell surface signaling molecules known as pattern recognition receptors (PRRs) that act as sensors of the external environment important for the innate immune system to detect 'self' from 'non-self' or 'altered self' are induced and/or expressed in cumulus cells as well as granulosa cells. These include the complement factor C1q, CD14 and the Toll-like receptors (TLRs) 4, 8 and 9 as well as mediators of TLR activation, MYD88 and IRF3. COCs exposed to bacterial LPS exhibit enhanced phosphorylation of p38MAPK, ERK1/2 and NF-kB and increased expression of Il6 and Tnfa target genes, documenting that the TLR pathway is functional. Cumulus cells and granulosa cells also express the scavenger receptors CD36 and SCARBI and exhibited phagocytic uptake of fluorescently-tagged bacterial particles. Collectively, these results provide novel evidence that cumulus cells as well as granulosa cells express innate immune related genes that may play critical roles in surveillance and cell survival during the ovulation process.
Expression regulated by
LH
Comment
Endocrine Society 2004
[P2-252] Involvement of Complement System in the Ovulation.
Giyoun Na, Mary C Gieske, CheMyong Ko, Yongbum Koo. Sch of Biotechnology and Biomed Sci, Inje Univ, Gimhae, Republic of Korea; Clin Scis, Univ of Kentucky, Lexington, KY
It is well known that the ovulation is an inflammatory-like process, which may involve the activation of complement system. Complement system is composed of various proteins that are sequentially activated by inflammatory signal resulting in the formation of membrane attack complex (MAC), which disrupts various types of cell membranes. At the site of inflammatory reaction, on the other hand, host cells produce regulators of complement systems which inhibit the MAC formation. In order to see whether complement system is involved in the ovulatory process, expression patterns of the membrane bound forms of regulators of complement activation (RCA) were examined in the periovulatory stage ovaries. For this purpose, a rat ovarian gene expression database (rOGED) was used. rOGED provides quantitative temporal mRNA expression profiles of 31,000 genes at ovarian (OVA), granulosa cell (GC), and non-granulosa/oocyte ovarian tissue (NGO) levels at various stages of follicular development (Abstract #852214). Of the three main types of RCAs, rOGED detected the expressions of mRNAs for membrane inhibitor of reactive lysis (CD59) and decay accelerating factor (DAF; CD55), but not membrane co-factor protein (MCP). CD59 mRNA was expressed both in GC and NGO all over the time points examined, with the peak expression at 12 h post treatment hCG. Expression of DAF mRNA was dramatically, yet transiently increased at 6 h post hCG treatment. Ten fold higher expression of DAF mRNA was detected in NGO than in GC at all time points examined. Northern blot analyses have confirmed the tissue- and time-dependent expression patterns of the rOGED data. We further examined the expression patterns of the various components of complement system. Surprisingly, within 6 hours of hCG treatment, two fold increase in mRNA expression was observed in the mRNAs for C1q , C3 and C4 proteins. Interestingly, those components were detected only in the NGO, except C1 that is expressed both in GC and NGO. The ovulatory inflammatory reaction is known to facilitate the process of follicle rupture. The inflammatory reaction, however, may give serious damages to the growing follicles, ovulated follicles and other important ovarian tissues. Present study strongly indicates that complement system may be involved in the ovulatory inflammation and the RCAs are expressed to protect ruptured follicles as well as other parts of the ovarian tissues from the potential attack by the complement system.
Ovarian localization
Granulosa
Comment
Follicle stages
Antral, Preovulatory
Comment
Phenotypes
Mutations
1 mutations
Species: ovine
Mutation name: type: naturally occurring fertility: fertile Comment: Genome-wide differential expression profiling of mRNAs and lncRNAs associated with prolificacy in Hu sheep. Feng X et al. (2018) Reproductive ability, especially prolificacy, impacts sheep profitability. Hu sheep, a unique Chinese breed, is recognized for its high prolificacy, early sexual maturity, and year-round estrus. However, little is known about the molecular mechanisms underlying high prolificacy in Hu sheep. To explore the potential mRNAs and long non-coding RNAs (lncRNAs) involved in Hu sheep prolificacy, we performed an ovarian genome-wide analysis of mRNAs and lncRNAs(Kung, 2013 #2) during the follicular stage using Hu sheep of high prolificacy (HP, litter size = 3; three consecutive lambings) and low prolificacy (LP, litter size = 1; three consecutive lambings). Plasma LH concentration was higher in the HP group than in the LP group (P < 0.05) during the follicular stage. Subsequently, 76 differentially expressed mRNAs (DE-mRNAs) and five differentially expressed lncRNAs (DE-lncRNAs) were identified by pairwise comparison; qRT-PCR analysis of 10 randomly selected DE genes (mRNA and lncRNA) were consistent with the sequencing results. Gene Ontology analysis of DE-mRNAs revealed significant enrichment in immune response components, actin filament severingand phagocytosis. Pathway enrichment analysis of DE-mRNAs indicated a predominance of immune function pathways, including phagosomes, lysosomes and antigen processing. We constructed a co-expression network of DE-mRNAs and mRNA-lncRNAs, withC1qA,CD53,CTSB,CTSS,TYROBP, andAIF1as the hub genes. Finally, the expression of lysosomal protease cathepsin genes,CTSBandCTSD,were significantly upregulated in sheep ovaries in the HP group compared to the LP group (P < 0.05). These differential mRNAs and lncRNAs may provide information on the molecular mechanisms underlying sheep prolificacy.//////////////////