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Cieslak J, Wodas L, Borowska A, Pawlak P, Czyzak-Runowska G, Wojtowski J, Puppel K, Kuczynska B, Mackowski M. 5'-flanking variants of equine casein genes (CSN1S1, CSN1S2, CSN2, CSN3) and their relationship with gene expression and milk composition. J Appl Genet 2018; 60:71-78. [PMID: 30328055 PMCID: PMC6373402 DOI: 10.1007/s13353-018-0473-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 12/22/2022]
Abstract
Genes encoding casein proteins are important candidates for milk composition traits in mammals. In the case of the domestic horse, our knowledge of casein genes is limited mainly to coding sequence variants. This study involved screening for polymorphism in 5’-flanking regions of four genes encoding equine caseins (CSN1S1, CSN1S2, CSN2, and CSN3) and making a preliminary assessment of their effect on the gene expression (on the mRNA and protein levels) and milk composition traits in selected horse breeds. Altogether, 23 polymorphisms (21 described previously SNPs and two novel InDels) were found in the studied sequences, the majority of which are common in various horse breeds. Statistical analysis revealed that some are putatively associated with gene expression or milk composition — for example, the c.-2047_-2048insAT polymorphism (CSN1S1) turns out to be related to the total milk protein content in Polish Primitive Horse (p < 0.05), whereas c.-2105C>G SNP (CSN2) is related to beta-casein relative mRNA level and milk lactose concentration in the Polish Coldblood Horse breed (p < 0.05). We have also found significant effects of horse breed and lactation time-point on gene expression and mare’s milk composition. Our study indicates that the 5’-regulatory regions of genes encoding casein proteins are interesting targets for functional studies of their expression and the composition traits of mare’s milk.
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Affiliation(s)
- Jakub Cieslak
- Department of Horse Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland.
| | - Lukasz Wodas
- Department of Horse Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland
| | - Alicja Borowska
- Department of Horse Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland
| | - Piotr Pawlak
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland
| | - Grazyna Czyzak-Runowska
- Department of Animal Breeding and Product QualityAssessment, Poznan University of Life Sciences, Sloneczna 1, 62-002, Zlotniki, Poland
| | - Jacek Wojtowski
- Department of Animal Breeding and Product QualityAssessment, Poznan University of Life Sciences, Sloneczna 1, 62-002, Zlotniki, Poland
| | - Kamila Puppel
- Department of Animal Science, Cattle Breeding Division, Warsaw University of Life Sciences, Ciszewskiego 8, 02-786, Warsaw, Poland
| | - Beata Kuczynska
- Department of Animal Science, Cattle Breeding Division, Warsaw University of Life Sciences, Ciszewskiego 8, 02-786, Warsaw, Poland
| | - Mariusz Mackowski
- Department of Horse Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland
- Horse Genetic Markers Laboratory, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland
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Cieslak J, Mackowski M, Czyzak-Runowska G, Wojtowski J, Puppel K, Kuczynska B, Pawlak P. Screening for the Most Suitable Reference Genes for Gene Expression Studies in Equine Milk Somatic Cells. PLoS One 2015; 10:e0139688. [PMID: 26437076 PMCID: PMC4593561 DOI: 10.1371/journal.pone.0139688] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/16/2015] [Indexed: 11/18/2022] Open
Abstract
Apart from the well-known role of somatic cell count as a parameter reflecting the inflammatory status of the mammary gland, the composition of cells isolated from milk is considered as a valuable material for gene expression studies in mammals. Due to its unique composition, in recent years an increasing interest in mare's milk consumption has been observed. Thus, investigating the genetic background of horse's milk variability presents and interesting study model. Relying on 39 milk samples collected from mares representing three breeds (Polish Primitive Horse, Polish Cold-blooded Horse, Polish Warmblood Horse) we aimed to investigate the utility of equine milk somatic cells as a source of mRNA and to screen the best reference genes for RT-qPCR using geNorm and NormFinder algorithms. The results showed that despite relatively low somatic cell counts in mare's milk, the amount and the quality of the extracted RNA are sufficient for gene expression studies. The analysis of the utility of 7 potential reference genes for RT-qPCR experiments for the normalization of equine milk somatic cells revealed some differences between the outcomes of the applied algorithms, although in both cases the KRT8 and TOP2B genes were pointed as the most stable. Analysis by geNorm showed that the combination of 4 reference genes (ACTB, GAPDH, TOP2B and KRT8) is required for apropriate RT-qPCR experiments normalization, whereas NormFinder algorithm pointed the combination of KRT8 and RPS9 genes as the most suitable. The trial study of the relative transcript abundance of the beta-casein gene with the use of various types and numbers of internal control genes confirmed once again that the selection of proper reference gene combinations is crucial for the final results of each real-time PCR experiment.
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Affiliation(s)
- Jakub Cieslak
- Department of Horse Breeding, Poznan University of Life Sciences, Poznan, Poland
| | - Mariusz Mackowski
- Department of Horse Breeding, Poznan University of Life Sciences, Poznan, Poland
| | - Grazyna Czyzak-Runowska
- Department of Small Mammals Breeding and Raw Materials of Animal Origin, Poznan University of Life Sciences, Poznan, Poland
| | - Jacek Wojtowski
- Department of Small Mammals Breeding and Raw Materials of Animal Origin, Poznan University of Life Sciences, Poznan, Poland
| | - Kamila Puppel
- Department of Animal Science, Cattle Breeding Division, Warsaw University of Life Sciences, Warsaw, Poland
| | - Beata Kuczynska
- Department of Animal Science, Cattle Breeding Division, Warsaw University of Life Sciences, Warsaw, Poland
| | - Piotr Pawlak
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Poznan, Poland
- * E-mail:
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