Increased expression of a novel splice variant of the complement component 4 (C4A) gene in mastitis-infected dairy cattle

Abstract

ABSTRACT. The complement system helps in the direct lysis of invading pathogens and modulates phagocytic, humoral and cellular immune responses. Complement 4 is a critical component in complement activity and protection against many bacterial pathogens because it is essential to classical and lectin activation pathways. We used reverse transcription and PCR to investigate alternative splicing and expression of the complement component 4 (C4A) gene in Chinese Holstein cattle. The PCR products were cloned and sequenced. A novel splice variant involving intron 10 was identified, which we named C4A-AS. To examine how C4A gene activity is affected by bovine mastitis, six Chinese Holstein cattle were divided into healthy (nonmastitic) and Staphylococcus aureus-induced mastitic groups. Realtime quantitative PCR (qRT-PCR) revealed that the C4A-complete and C4A-AS transcripts are expressed at significantly different levels in healthy cows, while there were no significant differences in the mastitic group (P = 0.257). Expression of C4A-AS increased significantly when mastitis developed. We also examined the expression of C4A-complete and C4A-AS in several tissues (liver, heart, spleen, lung, kidney, tongue, and muscle). The two transcripts were expressed in all of these tissues but there were no significant differences in expression between healthy and mastitic cows. We therefore conclude that the C4A-complete transcript is the main transcript under normal physiological conditions, while C4A-AS is augmented when mastitis develops.

Transcriptomics and iTRAQ-Proteomics Analyses of Bovine Mammary Tissue with Streptococcus agalactiae-Induced Mastitis

“…The complement system is a primary line of defense against infection . The bovine complement component 4 (C4A) was significantly associated with the susceptibility to intramammary infections by major pathogens . Günther et al.…”

“…27 The bovine complement component 4 (C4A) was significantly associated with the susceptibility to intramammary infections by major pathogens. 28 Gunther et al reported that mastitis could up-regulate the mRNA abundance of the C4A gene in E. coli-infected udders. 29 In the present study, the C4F gene and protein were down-regulated in the S. agalactiae group.…”

Molecular markers for resistance against infectious diseases of economic importance

“…[ 50 ] observed the SNP (g9788 C>T) where CC genotype was more prevalent than TT among Frieswal crossbreed cattle, and C allele was observed to be favorable for mastitis resistance and may be used as one of the molecular marker. RT-PCR analysis of C4A gene (chromosome 8) could reveal the SNP rs132741478: g.2994A>G in the coding sequence of the ß-chain and is found to be related with mastitis resistance [ 51 ].…”

Genetic mutations potentially cause two novel NCF1 splice variants up-regulated in the mammary gland, blood and neutrophil of cows infected by Escherichia coli

“…The expression of two new transcripts in these tissues and cells were up-regulated in response to mastitis infection. Alternative splicing is an important mechanism to regulate transcription and proteome complexity by producing multiple mRNAs from a single resistance or susceptibility-related gene, like LTF, SLAMF7, CLU, C4a and A2M that are found to be involved in mastitis resistance or susceptibility to mastitis (Huang et al, 2011;Ju et al, 2012;Wang et al, 2012a;Yang et al, 2012;Li et al, 2013). In human, NCF1 gene is accompanied by two almost similar (>99.5%) pseudogenes (NCF1B and NCF1C) which might arise by gene duplication (Görlach et al, 1997).…”