Promoter variants at AP2 box region of Hsp70.1 affect thermal stress response and milk production traits in Frieswal cross bred cattle.
Heat shock proteins (Hsp) are known to play major role in protection of cells from thermal stress. Nucleotide polymorphisms within the promoter of Hsp affect degree of expression and inducibility of Hsp mRNA. The present study aimed to investigate the effect of polymorphism within promoter region on the cellular expression of Hsp70.1 mRNA and association of identified polymorphisms with the physiological parameters during summer stress and milk production traits in dairy cattle. Two hundred Frieswal cows were genotyped using double PCR-RFLP to identify deletion of cytosine within the Hsp70.1 promoter AP2 box at base position 895. Homozygous wild type genotypes (CC) were found in lower frequency (39.29, n=78) than heterozygous cytosine deletion mutant genotypes (C-) (60.71, n=122). In the observed physiological parameters (rectal temperature, respiration rate and heat tolerance coefficient), cows that were homozygous wild types had better significant (P<0.05) summer tolerance than the heterozygous deletion genotypes. Cytosine deletion mutation in the promoter region negatively affected (P<0.01) the expression of Hsp70.1 mRNA in peripheral bovine mononuclear cells (PBMC) subjected to in vitro heat stress. Further association of observed polymorphism with the milk production traits was significant as the heterozygous cytosine deletion cows had lower total milk yield, peak yield, yield at 300 days, protein% (P<0.01) and fat% (P<0.05) than the native wild type promoter cows. The results from the present study suggest that the promoter region of bovine hsp70.1 gene is polymorphic and may be useful in selection of dairy cows for relatively better thermotolerance and higher milk production.
Molecular Genetics Laboratory, Animal Genetics and Breeding Section Project Directorate on Cattle, Indian Council of Agricultural Research, Grass Farm Road, P. O. Box 17, Meerut Cantt., Meerut 250 001, Uttar Pradesh, India. Electronic address: drrajibdeb@gmail.com.
Rajib
R
Deb
Basavaraj
B
Sajjanar
Umesh
U
Singh
Sushil
S
Kumar
M P
MP
Brahmane
Rani
R
Singh
G
G
Sengar
Arjava
A
Sharma
D000818:Animals; D001665:Binding Sites; D002417:Cattle / Q000235:genetics*; D002478:Cells, Cultured; D005260:Female; D015870:Gene Expression; D005787:Gene Frequency; D056726:Genetic Association Studies; D050884:HSP72 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018869:Heat-Shock Response; D007774:Lactation / Q000235:genetics*; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008892:Milk / Q000378:metabolism*; D010641:Phenotype; D012150:Polymorphism, Restriction Fragment Length; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D015533:Transcriptional Activation
D050884:HSP72 Heat-Shock Proteins
AP2 box; ARR; ART; HF; HTC; Holstein Friesian; Hsp; Hsp70.1; Milk production; PBMC; PPIA; Polymorphism; Promoter; RFLP; RH; Thermotolerance; average rectal temperature; average respiratory rate; heat shock protein; heat tolerance coefficient; peptidyl prolylisomerise A; peripheral bovine mononuclear cells; qPCR; quantative polymerase chain reaction; relative humidity; restriction fragment length polymorphism