Increased expression of a  novel splice variant of the complement component 4 (C4A) gene in  mastitis-infected dairy cattle.
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 (non-mastitic) and Staphylococcus aureus-induced  mastitic groups. Real-time 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.
Dairy Cattle Science Research Center, Shandong Academy of Agricultural Sciences, Jinan, P.R. China.
Y
Y
Yang
J M
JM
Huang
Z H
ZH
Ju
Q L
QL
Li
L
L
Zhou
R L
RL
Li
J B
JB
Li
F X
FX
Shi
J F
JF
Zhong
C F
CF
Wang
D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D002417:Cattle / Q000235:genetics* / Q000276:immunology*; D002681:China; D015934:Complement C4a / Q000235:genetics*; D003612:Dairying; D005260:Female; D008414:Mastitis, Bovine / Q000235:genetics* / Q000276:immunology* / Q000382:microbiology; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013211:Staphylococcus aureus / Q000502:physiology
D012333:RNA, Messenger; D015934:Complement C4a