Diacylglycerol Acyltransferase Enzimini Kodlayan DGAT1 Genindeki K232A Mutant Allelinin Saptanması

Abstract

DGAT1 geni triacylglycerol (trigliserid) sentezinde önemli bir rol oynayan Diacylglycerol acyltransferase enzimini kodlamaktadır. DGAT1 sığırlarda 14. kromozomunun sentromerik bölgesinde yer alan, sütteki yağ oranını arttırmasına neden olduğu bilinen bir kantitatif özellik lokusudur (QTL). 232. aminoasit bölgesinde bir lizin aminoasidinin alanine dönüştüğü nokta RFLP ile tespit edilmiştir. Bu çalışmanın amacı İstanbul Üniversitesi Veteriner Fakültesi Eğitim, Araştırma ve Uygulama Çiftliğine ait olan İsviçre Esmeri ve Holştayn sığır ırklarında K232A mutasyonu ile K ve A allellerinin frekansını saptamaktır. KK, KA ve AA genotiplerinin ayırt edilmesinde CfrI enzimi kullanılmıştır. DNA bantları %2’lik agaroz jel elektroforezinde görüntülenmiştir. İncelenen Holştayn ve İsviçre Esmeri sığır ırklarında K ve A allellerinin frekansları sırasıyla 0.287 ve 0.713 ile 0.091 ve 0.901 olarak bulunmuştur. Bu araştırma makalesi Türkiye’deki diğer sığır ırklarında DGAT1 K ve A allellerinin frekanslarını saptamaya yönelik bir ön çalışma niteliği taşımaktadır.

Keywords

• DGAT1,Holştayn,İsviçre Esmeri,RFLP

Identification of K232A mutant allele of DGAT1 Gene Encoding Diacylglycerol Acyltransferase Enzyme

Abstract

DGAT1 gene encodes Diacylglycerol acyltransferase enzyme that plays a key role in triacylglycerol (triglyceride) synthesis. DGAT1 is a quantitative trait locus (QTL) that has an effect on increasing milk fat content in the centromeric region of bovine chromosome 14. Lysine (K)→Alanin (A) mutation that resulted in AA genotypes decreases milk fat rate and increases milk yield. The substitution of lysine amino acid to alanin at position 232 was identified with CfrI enzyme. The aim of this study was to identify both K232A mutation and the frequency of K and A alleles among Brown Swiss and Holstein cattle breeds which belong to Education Research and Application Farm of Istanbul University Veterinary Faculty. RFLP was used to distinguish KK, KA and AA genotypes. PCR products were screened by 2% agarose gel electrophoresis. K allele and A allele frequencies among 54 Holstein and 44 Brown Swiss cattle breeds were 0.287 and 0.713, 0.091 and 0.901 respectively. This research article constitutes the pre-study of frequency determination of DGAT1 K and A alleles in Turkish native cattle breeds.

Keywords

• Brown Swiss,DGAT1,Diacylglycerol acyltransferase,Holstein,RFLP

References

1. Chen HC. Enhancing energy and glucose metabolism by disrupting triglyceride synthesis: Lessons from mice lacking DGAT1. Nutr Metab 2006; 3 (10):1-4.
2. 2. Buhmann KK, Smith SJ, Stone SJ, Repa JJ, Wong JS, Knapp JrFF, Burri BJ, Hamilton RL, Abumrad NA, Farese JrRR. DGAT1 is not essential for intestinal triacylglycerol absorption or chlomicron synthesis. The Jour of Biol Chem 2002; 277 (28): 25474-9.
3. 3. Cases S, Smith SJ, Zheng YW, Myers HM, Lear SR, Sande E, Novak S, Collins C, Welch CB, Lusis AJ, Erickson SK, Farese JrRV. Identification of a gene encoding an acyl CoA:diacylglycerol acyltransferase, a key enzyme in triacylglycerol synthesis. Proc Natl Acad Sci 1998; 95 (22): 13018-3.
4. 4. Cassas E, White SN, Riley DG, Smith TPL, Brenneman RA, Olson TA, Johnson DD, Coleman SW, Bennett GL, Chase JrCC. Assessment of single nucleotide polymorphisms in genes residing on chromosomes 14 and 29 for association with carcass composition traits in Bos indicus cattle. J Anim Sci 2005; 83 (1):13-9.
5. 5. Cerit H, Altınel A, Elmaz O, Avanus K. Polymorphism evaluation of various genomic loci in Kivircik sheep breed of Turkey. Turk J Vet Anim Sci 2004; 28 (2): 415-5.
6. 6. Chen HC, Smith SJ, Ladha Z, Jensen DR, Ferreira LD, Pulawa LK, McGuire JG, Pitas RE, Eckel RH, Farese JrRV. Increased insulin and leptin sensitivity in mice lacking acyl CoA: diacylglycerol acyltransferase 1. J Clin Invest 2002; 109 (8): 1049-5.
7. 7. Dekkers JCM. Commercial application of marker- and gene- assisted selection in livestock: strategies and lessons. J Anim Sci 2004; 82 (E-Suppl): 313-8.
8. 8. Fisher PJ, Spelman RJ. Verification of selective DNA pooling methodology through identification and estimation of the DGAT1 effect. Anim Genet 2004; 35 (3): 201-5.

9. 9. Grisart B, Coppieters W, Farnir F, Karim L, Ford C, Berzi P, Cambisano N, Mni M, Reid S, Simon P, Spelman R, Gearges M, Snell R. Positional candidate cloning of a QTL in dairy cattle: Identification of a missence mutation in the bovine DGAT1 gene with major effect on milk yield and composition. Genome Res 2001; 12 (2): 222-1.
10. 10. Grisart B, Farnir F, Karim L, Cambisano N, Kim JJ, Kvasz A, Mni M, Simon P, Frére JM, Coppieters W, Georges M. Genetic and functional confirmation of the causality of the DGAT1 K232A quantitative trait nucleotide in affecting milk yield and composition. PNAS 2004; 101 (8):2398-403.
11. 11. Hobbs DH, Lu C, Hills MJ. Cloning of a cDNA encoding diacylglycerol acyltransferase from Arabidopsis thaliana and its functional expression. FEBS Letters 1999; 452 (3): 145-9.
12. 12. Kaupe B, Winter A, Fries R, Erhadt G. DGAT1 polymorphism in Bos indicus and Bos taurus cattle breeds. J Dairy Res 2004; 71 (2): 182- 7.
13. 13. Kühn C, Thaller G, Winter A, Emonds ORPB, Kaupe B, Erhardt G, Bennewitz J, Schwerin M, Fries R. Evidence for multiple alleles at the DGAT1 locus better explains a quantitative trait locus with major effect on milk fat content in cattle. Genetics 2004; 167 (4): 1873-81.
14. 14. Mercadé A, Sanchez A, Folch JM. Exclusion of the acyl CoA: diacylglycerol acyltransferase 1 gene (DGAT1) as a candidate for fatty acid composition QTL on porcine chromosome 4. J Anim Breed Genet 2005; 122 (3): 161-4.
15. 15. Moore SS, Li C, Basarab J, Snelling WM, Kneeland J, Murdoch B, Hansen C, Benkel B. Fine mapping of quantitative trait loci and assessment of positional candidate genes for backfat on bovine chromosome 14 in a commercial line of Bos taurus. J Anim Sci 2003; 81 (8): 1919-5.
16. 16. Nonneman D, Rohrer GA. Linkage mapping of porcine DGAT1 to a region of chromosome 4 that contains QTL for growth and fatness. Anim Genet 2002; 33 (6): 472-3.
17. 17. Raymond M, Rousset F 1995, GENEPOP (Version 1.2) Population genetics software.
18. 18. Scnabel RD, Sonstegard TS, Taylor JF, Ashwell MS. Whole-genome scan to detect QTL for milk production conformation, fertility and functional traits in two US Holstein families. Anim Genet 2005; 36 (5): 408-6.
19. 19. Spelman RJ, Ford CA, McElhinney P, Gregory GC, Snell RG. Characterization of the DGAT1 gene in the New Zealand dairy population. J Dairy Sci 2002; 85 (12): 3514-7.
20. 20. Thaller G, Krämer W, Winter A, Kaupe B, Erdhardt G, Fries R. Effects of DGAT1 variants on milk production traits in German cattle breeds. J Anim Sci 2003; 81 (8): 1911-8.
21. 21. Thaller G, Kühn C, Winter A, Ewald G, Bellmann O, Wegner J, Zühlke H, Fries R. DGAT1, a new positional and functional candidate gene for muscular fat deposition in cattle. Anim Genet 2003; 34 (5): 354-7.
22. 22. Weller JI, Golik M, Seroussi E, Ezra E, Ron M. Population-wide analysis of a QTL affecting milk-fat production in the Israeli Holstein population. J Dairy Sci 2003; 86 (6): 2219-7.
23. 23. Winter A, Alzinger A, Fries R. Assessment of the gene content of the chromosomal regions flanking bovine DGAT11. Genomics 2004; 83 (1): 172-80.
24. 24. Winter A, Eckeveld MV, Emonds ORPB, Habermann FA, Fries R: Genomic organization of the DGAT2/MOGAT gene family in cattle (Bos taurus) and other mammals. Cytogenet Genome Res 2003;102 (1-4): 42-7.
25. 25. Winter A, Krämer W, Werner FAO, Kollers S, Kata S, Durstewitz G, Buitkamp J, Womack JE, Thaller G, Fries R. Association of lysine-232/alanine polymorphism in a bovine gene encoding acyl-coA: diacylglycerol acyltransferase (DGAT1) with variation at a quantitative trait locus for milk fat content. PNAS 2002; 99 (14): 9300-5.
26. 26. Winter A. Genomic characterization of genes encoding diacylglycerol acyltransferase activity in cattle and swine. PhD Dissertation. Technisce Universität München, Lehrstuhl für Tierzucht, Munich, Germany, 2003.