Bovine Insulin-like Growth Factor Research Articles

Association of polymorphisms in IGF2, CLU and STAT5A genes with milk production characteristics in Chinese Holstein cattle

Reflecting the quality of milk at the molecular level is a frontier technology. The aim of this study was to analyze the polymorphisms of bovine insulin-like growth factor 2 (<i>IGF2</i>), signal transducer and activator of transcription 5A (<i>STAT5A</i>) and clusterin (<i>CLU</i>) genes in the raw milk from 507 Chinese Holstein cow using polymerase chain reaction (PCR)-restriction fragment length polymorphism techniques and to evaluate their correlations with the milk protein content (MPC), milk fat content (MFC), milk lactose content (MLC) and milk total solids content (MTSC). In <i>IGF2</i> gene, genotype GG was the most frequent genotype (51.68%) followed by the genotype GT (38.03%) and TT (10.29%). And the genotype TT of <i>IGF2</i> gene was superior to the other genotypes in MPC. In <i>CLU</i> gene, genotype GG was the most common genotype (63.99%) followed by the genotype GA (34.45%) and AA (1.56%). And the genotype AA of <i>CLU</i> gene had greater MFC and MLC, but lower MTSC than GA genotype individuals. For <i>STAT5A</i> gene, the frequency of genotype CC and CT was similar (45.30% and 45.08%), while the genotype TT had lowest frequency (9.62%). And the genotype TT of <i>STA5A</i> gene had highest MPC and lowest MLC. Thus, screening for the <i>IGF2</i>, <i>CLU</i> and <i>STAT5A</i> genes were available for evaluating milk quality and raw milk samples were graded according to the different genotypes.

CDNA Cloning of a Bovine Insulin-like growth factor-1 from Egyptian Buffalos and Expression of its Recombinant Protein in Escherichia coli

ABSTRACT Insulin-like growth factor-1 (IGF-1) is regarded as a crucial clinically significant therapeutic agent against several pathological conditions. Recently, recombinant DNA (rDNA) technology has enabled the production of many drugs of rDNA-origin including IGF-1. Securing a readily available supply of IGF-1 is invaluable to clinical research and biotechnological domains. In this work, the cloning of a full-length bovine IGF-1 cDNA and the successful expression of its cognate recombinant IGF-1 protein is reported. Single-strand cDNA was prepared from liver tissues, through the specific reverse transcription (RT) of IGF-1 mRNA. Subsequently, a PCR amplicon of ~543bp was successfully amplified. Recombinant pTARGET™ vector harboring IGF-1 insert was successfully cloned into competent E. coli JM109 cells. SDS-PAGE analysis revealed that the recombinant IGF-1 has been expressed at the expected size of 7.6kDa. The outcome provides a robust basis for transecting the recombinant pTARGETTM vector, harboring the IGF-1 cDNA insert, into mammalian cells. Optimal initial glucose concentration was found to be 10g/l with corresponding protein concentration of 6.2g/l. The proliferative biological activity crude recombinant IGF-1 protein was verified on HeLa cell lines. This is envisaged to facilitate large-scale production of recombinant IGF-1 protein, thereby enabling thorough investigation of its clinical and pharmaceutical effects.

Relationship of the bovine IGF1, TG, DGAT1 and MYF5 genes to meat colour, tenderness and cooking loss

Bovine insulin-like growth factor 1 (IGF1), thyroglobulin (TG), diacylglycerol-O-acyltransferase 1 (DGAT1) and myogenic factor 5 (MYF5) genes play an important role in the physiology of lipid and muscle metabolism and are therefore considered as candidate genes for meat production traits in farm animals. The objectives of this study were to investigate single nucleotide polymorphisms (SNPs) in IGF1, TG, DGAT1 and MYF5 genes and to evaluate whether these polymorphisms affected meat colour, tenderness and cooking loss in Holstein cattle. Initially, the SNPs were detected by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) method. Meat samples (N= 50) derived from M. longissimus thoracis et lumborum (LTL) were used in the current study. Significant differences in variations of meat colour parameters were observed at 24 hours post-mortem. IGF1 was associated with colour parameters of a* and chroma values. In addition, effects of TG were statistically significant on L* and a* values, while, effects of MYF5 were significant on a* value. There was no association of the tested SNPs with meat pH, tenderness and cooking loss. The results presented here may give the valuable information for improving meat colour in cattle.

Atlas of tissue- and developmental stage specific gene expression for the bovine insulin-like growth factor (IGF) system.

The insulin-like growth factor (IGF) axis is fundamental for mammalian growth and development. However, no comprehensive reference data on gene expression across tissues and pre- and postnatal developmental stages are available for any given species. Here we provide systematic promoter- and splice variant specific information on expression of IGF system components in embryonic (Day 48), fetal (Day 153), term (Day 277, placenta) and juvenile (Day 365–396) tissues of domestic cow, a major agricultural species and biomedical model. Analysis of spatiotemporal changes in expression of IGF1, IGF2, IGF1R, IGF2R, IGFBP1-8 and IR genes, as well as lncRNAs H19 and AIRN, by qPCR, indicated an overall increase in expression from embryo to fetal stage, and decrease in expression from fetal to juvenile stage. The stronger decrease in expression of lncRNAs (average ―16-fold) and ligands (average ―12.1-fold) compared to receptors (average ―5.7-fold) and binding proteins (average ―4.3-fold) is consistent with known functions of IGF peptides and supports important roles of lncRNAs in prenatal development. Pronounced overall reduction in postnatal expression of IGF system components in lung (―12.9-fold) and kidney (―13.2-fold) are signatures of major changes in organ function while more similar hepatic expression levels (―2.2-fold) are evidence of the endocrine rather than autocrine/paracrine role of IGFs in postnatal growth regulation. Despite its rapid growth, placenta displayed a more stable expression pattern than other organs during prenatal development. Quantitative analyses of contributions of promoters P0-P4 to global IGF2 transcript in fetal tissues revealed that P4 accounted for the bulk of transcript in all tissues but skeletal muscle. Demonstration of IGF2 expression in fetal muscle and postnatal liver from a promoter orthologous to mouse and human promoter P0 provides further evidence for an evolutionary and developmental shift from placenta-specific P0-expression in rodents and suggests that some aspects of bovine IGF expression may be closer to human than mouse.

Sequence Characterization of Bovine Antisense to Insulin-Like Growth Factor Type 2 Receptor Non-Coding RNA (AIRN)

Bovine insulin-like growth factor type 2 receptor (IGF2R) is an imprinted gene whose aberrant expression has been implicated in development of abnormal offspring syndrome. Bovine AIRN (AIRN) is expressed in post-implantation fetal tissues coinciding with imprinted expression of IGF2R. Although expression patterns of bovine AIRN have been reported based on PCR analysis, characteristics of this transcript are unknown. Therefore, the objective of this work was to sequence characterize the AIRN ncRNA transcript. PCR primer sets (n = 19) were designed based on genomic sequence to “walk” down the predicted AIRN ncRNA sequence. Total RNA extracted from gestational day 150 bovine fetal liver was used as source material for analysis. Extracted RNA was DNase-treated prior to cDNA synthesis, PCR amplified, and sequenced. A putative bAIRN promoter was located 623 base-pairs upstream of differentially methylated region 2 (DMR2) within intron 2 of IGF2R. A polyadenylation signal was found 117 kb downstream of the promoter. Primer sets designed upstream of the promoter as well as downstream of the polyadenylation signal yielded no PCR amplicons, suggesting that the length of AIRN is approximately 117 kb. In conclusion, bovine AIRN appears to be an antisense transcript of approximately 117 kb in length with a promoter region located 623 bp upstream of DMR2 within intron 2 of IGF2R.

Polymorphism in exon 2 encoding the putative ligand binding pocket of the bovine insulin-like growth factor 1 receptor affects milk traits in four different cattle breeds.

As a member of the somatotropic axis, insulin-like growth factor I receptor (IGF1R) seems to be a promising candidate gene. Two silent polymorphisms, identified by MspI and TaqI restriction enzymes, were selected within exon 2, encoding the majority of the putative ligand binding pocket. A total of 1169 cows of four pure breeds (Polish Holstein Friesian, Montbeliarde, Jersey and Holstein Friesian) were genotyped. The T (IGF1R/e2/MspI) and G (IGF1R/e2/TaqI) alleles were found to be prevalent. Three combinations of genotypes (TT/GG, TT/AG and CT/GG) were associated with the highest productivity (milk, protein and fat yields) among all breeds under study, as opposed to individuals carrying the worst CC/AA combination. In view of the specific structure of the ligand binding pocket and the significance of insulin-like growth factor I signalling promoting the development and differentiation in a variety of tissues (not only limited to mammary gland), the existence of missense mutation is unlikely. Potential mutations are likely limited to mRNA transcription and further post-transcriptional modifications. Further investigations should follow searching for the most useful IGF1R haplotypes, associated with higher milk production traits, exerting at the same time positive or neutral impact on health and welfare of individuals.

Genetic variability of bovine GHR, IGF-1 and IGFBP-3 genes in Indian cattle and buffalo

The identification of genetic polymorphisms in the genes that play a crucial role in regulatiing growth and development of livestock enables us to evaluate the biological similarities and to acquire a better perspective of quantitative traits. The present study was undertaken to characterize genetic variability in the bovine growth hormone receptor (GHR), insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) genes among Bos indicus (Malnad Gidda, Khillar), Bos taurus (Holstein Friesian, Jersey) cattle and Asian water buffalo Bubalus bubalis (Murrah, Surti) using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis. These polymorphisms were confirmed by direct sequencing. The comparative gene sequence analysis in cattle and buffalo breeds revealed 18 single nucleotide polymorphisms (SNPs) across different loci. Eight SNPs were detected in the bovine growth hormone receptor (GHR) gene, of which four were found in the promoter region and four in the exon 4 region. In the IGF-1 gene, two SNPs were observed in the 5ˈUTR, three SNPs in the intron 3 region and two SNPs in the coding region of exon 4. Three SNPs were detected in the exon 2 region of the bovine IGFBP-3 gene. The frequency of rare alleles observed in the present study ranged from 0.04 to 0.16. The present results revealed high levels of genetic variability in the GHR, IGF-1 and IGFBP-3 genes in cattle and buffalo reared in India. Keywords: PCR-SSCP, genetic polymorphism, cattle, buffalo

Polymorphism of the Insulin-like growth factor 1 receptor gene (IGF1R/e10/MspI and IGF1R/e16/RsaI) in four dairy breeds and its association with milk traits

Studying candidate genes for significant economic traits could be directly applied in a search for quantitative trait loci. There is growing evidence that the IGF-I/IGF-1R signaling pathway can be involved in mammary gland development and milk synthesis control. The bovine Insulin-like growth factor 1 receptor gene encodes a transmembrane ligand-activated tyrosine protein kinase. The presence of two synonymous mutations (IGF1R/e10/MspI and IGF1R/e16/RsaI) have been validated in 4 dairy breeds (Polish Holstein-Friesian, Holstein-Friesian, Montbeliarde and Jersey). A total of 1167 blood samples were genotyped. Five milk performance traits, i.e., milk yield (MY), fat yield (FY), protein yield (PY), fat percentage (F%), and protein percentage (P%) were used in the association analysis. The data for the full 305-day milk production (1st, 2nd and 3rd lactation, collected between 2007 and 2014) were obtained from the official farm records. The TT genotype of both polymorphisms was found to be associated with the highest yields (milk yield – MY, fat yield – FY and protein yield – PY), while the lowest values were recorded for the CC genotype (P≤0.01). In order to confirm or refute the association found, statistical analysis of the combined genotypes was also performed. Irrespective of breed and lactation order, cows with the TT/TT genotype combination were usually characterized by the highest milk, fat and protein yields, as opposed to the least favorable CC/CC combination. As regards the milk yield, the differences were in the range of 2000kg (MO) to 3000kg per lactation (PHF, HF) (P≤0.01). Significant differences at the level of 80÷130kg for FY and 50÷100kg for PY were also recorded (P≤0.01). No statistical differences in fat and protein content were found. In light of these results, the IGF1R gene can be proposed as a candidate gene for milk traits in cattle.

SNP exploring in the middle and terminal regions of the IGF-1 gene and association with production and reproduction traits in Holstein cattle

Five primer sets were designed in order to identify single nucleotide polymorphisms (SNPs) in middle and terminal exons (2 to 6) and in some flanking intronic regions of the bovine insulin-like growth factor 1 (IGF-1) gene. Sequencing results of PCR products for 10% of animals showed no variant in exons but a SNP at intron 4 was occurred. Both polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) and high resolution melting (HRM) methods were developed to genotype samples. The PCR–RFLP results showed the presence of three fragments on agarose gel for the C allele due to two cleavage sites while two fragments for the T allele were observed. Melting curves of 123bp fragments in HRM analysis showed a difference between temperature melting (Tm) of two homozygous genotypes as the CC genotypes had higher Tm than the TT genotypes. Melting curve of the CT genotype was different and crossed two parallel patterns of homozygous genotypes. The frequencies of the CC, CT and TT genotypes were 0.6, 0.37 and 0.03, respectively. Also, the estimated allele frequencies were 0.785 and 0.215 for the C and T alleles, respectively. Results showed higher accuracy of the HRM analysis compared to the PCR–RFLP method. Least square means (LSMs) comparison of the different genotypes in the SNP showed significant association with milk fat yield trait in the first lactation and open days after the second calving. The polymorphism did not have a significant effect on other milk production or reproduction traits. It seems that other variants or QTLs known in this region underlie genetic variation in the production and reproduction of dairy cattle.

SNP and haplotype analysis reveal IGF2 variants associated with growth traits in Chinese Qinchuan cattle

Insulin-like growth factor 2 (IGF2) is a potent cell growth and differentiation factor and is implicated in mammals' growth and development. The objective of this study was to evaluate the effects of the mutations in the bovine IGF2 with growth traits in Chinese Qinchuan cattle. Four single nucleotide polymorphisms (SNPs) were detected of the bovine IGF2 by DNA pool sequencing and forced polymerase chain reaction-restriction fragment length polymorphism (forced PCR-RFLP) methods. We also investigated haplotype structure and linkage disequilibrium (LD) coefficients for four SNPs in 817 individuals representing two main cattle breeds from China. The result of haplotype analysis showed eight different haplotypes and 27 combined genotypes within the study population. The statistical analyses indicated that the four SNPs, combined genotypes and haplotypes are associated with the withers height, body length, chest breadth, chest depth and body weight in Qinchuan cattle population (P<0.05 or <0.01). The mutant-type variants and mutant haplotype (Hap 8: ATGG; likely to be the beneficial QTN allele) was superior for growth traits; the heterozygote diplotype was associated with higher growth traits compared to wild-type homozygote. Our results provide evidence that polymorphisms in the IGF2 gene are associated with growth traits, and may be used for marker-assisted selection in beef cattle breeding program.

Intragenic DNA methylation status down-regulates bovine IGF2 gene expression in different developmental stages

DNA methylation is a key epigenetic modification in mammals and has an essential and important role in muscle development. Insulin-like growth factor 2 (IGF2) is a fetal growth and differentiation factor that plays an important role in muscle growth and in myoblast proliferation and differentiation. The aim of this study was to evaluate the expression of IGF2 and the methylation pattern on the differentially methylated region (DMR) of the last exon of IGF2 in six tissues with two different developmental stages. The DNA methylation pattern was compared using bisulfite sequencing polymerase chain reaction (BSP) and combined bisulfite restriction analysis (COBRA). The quantitative real-time PCR (qPCR) analysis indicated that IGF2 has a broad tissue distribution and the adult bovine group showed significant lower mRNA expression levels than that in the fetal bovine group (P<0.05 or P<0.01). Moreover, the DNA methylation level analysis showed that the adult bovine group exhibited a significantly higher DNA methylation levels than that in the fetal bovine group (P<0.05 or P<0.01). These results indicate that IGF2 expression levels were negatively associated with the methylation status of the IGF2 DMR during the two developmental stages. Our results suggest that the methylation pattern in this DMR may be a useful parameter to investigate as a marker-assisted selection for muscle developmental in beef cattle breeding program and as a model for studies in other species.

Assessment of association between variants and haplotypes of the IGF2 gene in beef cattle

Insulin-like growth factor 2 (IGF2) is a fetal growth and differentiation factor that plays an important role in muscle growth and in myoblast proliferation and differentiation. The aim of this study was to examine the association of the IGF2 polymorphism with growth traits in beef cattle breed. Four single nucleotide polymorphisms (SNPs: 1–4) were identified in the bovine IGF2 by sequencing pooled DNA samples (Pool-Seq) and forced polymerase chain reaction–restriction fragment length polymorphism (Forced PCR–RFLP) methods. The result of haplotype analysis of four SNPs showed that eight haplotypes and eighteen combined genotypes were revealed, and the linkage disequilibrium and evolutionary relationship were assessed in 1522 individuals representing four purebred cattle breeds from China. The statistical analyses indicated that the 4 SNPs and 18 combined genotypes or haplotypes are associated with the body weight at 18 and 24months in Jiaxian cattle population (P<0.05 or P<0.01). Our results provide evidence that polymorphisms in the IGF2 gene are associated with growth traits, and may be used for marker-assisted selection in beef cattle breeding program.

Comparative analysis of the IGF2 and ZBED6 gene variants and haplotypes reveals significant effect of growth traits in cattle

Muscle growth is a complex phenomenon regulated by many factors, whereby net growth results from the combined action of synthesis and turnover. Insulin-like growth factor 2 (IGF2) is a fetal growth and differentiation factor that plays an important role in muscle growth and in myoblast proliferation and differentiation; Zinc finger, BED-type containing 6 (ZBED6) is a novel transcription factor that was identified and shown to act as a repressor of IGF2 transcription in skeletal muscle. In this study, a total of seven single nucleotide polymorphisms (SNPs) were identified, four SNPs in intron 8 of IGF2 and one promoter SNP and two missense mutations in the coding region of ZBED6, two of which were in complete linkage disequilibrium (LD) in the bovine IGF2. The 58 haplotypes were inferred in 1522 individuals representing four purebred cattle breeds from China. The seven SNPs, 79 and 66 combined diplotypes were revealed for association with body mass in Nanyang and Jiaxian cattle populations at five different ages (P < 0.05 or 0.01). The mutant-type variants and haplotype 58 (likely in LD with the beneficial quantitative trait nucleotide allele) was superior for body mass; the heterozygote diplotype of the most common haplotypes 58 was associated with higher body mass compared to either heterozygote or homozygote. The statistical analyses indicated that the mutant-type variants and haplotypes are significantly associated with body mass in study cattle populations at different ages. These data demonstrate that variants and haplotypes are associated with growth traits, and these results may provide important biological insights into the phenotypic differentiation that is associated with adaptation and specialization of cattle breeds.

Allelic gene expression imbalance of bovine IGF2, LEP and CCL2 genes in liver, kidney and pituitary

Allelic expression imbalance (AEI) is an important genetic factor being the cause of differences in phenotypic traits that can be heritable. Studying AEI can be useful in searching for factors that modulate gene expression and help to understand molecular mechanisms underlying phenotypic changes. Although it was commonly recognized in many species and we know many genes show allelic expression imbalance, this phenomena was not studied on a larger scale in cattle. Using the pyrosequencing method we analyzed a set of 29 bovine genes in order to find those that have preferential allelic expression. The study was conducted in three tissues: liver, pituitary and kindey. Out of the studied group of genes 3 of them—LEP (leptin), IGF2 (insulin-like growth factor 2), CCL2 (chemokine C–C motif ligand 2) showed allelic expression imbalance.Electronic supplementary materialThe online version of this article (doi:10.1007/s11033-012-2161-3) contains supplementary material, which is available to authorized users.

140 CHARACTERIZATION OF THE BOVINE ANTISENSE TO INSULIN-LIKE GROWTH FACTOR TYPE 2 RECEPTOR (bAIRN) NONCODING RNA

Bovine insulin-like growth factor type 2 receptor (IGF2R) is an imprinted gene whose aberrant expression has been implicated in development of abnormal offspring syndrome. Gene IGF2R is a member of the IGF2R/AIRN imprinted gene cluster located on chromosome 9 in cattle. This imprinting cluster is flanked on the proximal 5′ end by MAS1. In the mouse, the antisense to Igf2r noncoding RNA, Airn, is a 108-kb polyadenylated transcript that regulates imprinted expression of Igf2r and other genes within the Igf2r/Airn cluster in association with implantation. Bovine AIRN (bAIRN) is expressed in post-implantation fetal tissues with expression coincident with imprinted expression of IGF2R. Further characterisation of bAIRN is needed before investigation of its potential role in regulating imprinted expression of IGF2R in cattle can be pursued. Therefore, the objective of this study was to identify the length and key characteristics of the bAIRN ncRNA transcript. The PCR primer sets (n = 26) were designed based on genomic sequences to walk down the predicted bAIRN ncRNA sequence by amplifying key segments located along the transcript. Total RNA, extracted from gestational day 150 bovine fetal liver, was DNase-treated to eliminate contaminating genomic DNA. The DNase-treated RNA was then used to generate cDNA as a template for PCR amplification. A putative promoter region containing the transcriptional start site for bAIRN was identified based on NCBI sequence data. This bAIRN promoter is located 441 bp upstream of differentially methylated region 2 (DMR2) within intron 2 of IGF2R and contains a CAAT-box, GC-box and TATA-box. The PCR primer sets (n = 2) designed to amplify products upstream of the putative promoter failed to produce any PCR amplicons. However, PCR primer sets (n = 6) designed to amplify segments located from 4 to 10 kb downstream of the putative promoter region produced amplicons that were sequence verified to be bAIRN ncRNA. Additional PCR primer sets (n = 3) produced sequence-verified amplicons that were located ∼27, 45 and 52 kb downstream of the putative bAIRN transcription start site. Between 27 and 44 kb downstream of the bAIRN promoter, a series of sequence duplications from MAS1 were identified within the bAIRN ncRNA. The role of these duplicated regions is currently unknown. Three PCR primer sets (n = 3) designed to amplify consecutive regions spanning from 93.4 to 101 kb downstream of the bAIRN promoter failed to produce amplicons, suggesting prior termination of the bAIRN transcript. In addition, a strong putative polyadenylation signal was identified at 65.4 kb downstream from the bAIRN promoter. In summary, the full-length bAIRN ncRNA has been characterised. The bAIRN promoter is located ∼440 bp upstream of DMR2 on the IGF2R antisense strand. Transcription from the bAIRN promoter results in a noncoding RNA with a length of ∼65 kb. The central third of the bAIRN transcript contains a series of sequence duplications from MAS1. The function of these duplications within the bAIRN ncRNA is currently unknown. This research was supported by the North Carolina Agricultural Experiment Station.

Single Nucleotide Polymorphisms in the Insulin-Like Growth Factor 1 (IGF-1) Gene are Associated with Performance in Holstein-Friesian Dairy Cattle

Insulin-like growth factor 1 (IGF-1) has been shown to be associated with fertility, growth, and development in cattle. The aim of this study was to (1) identify novel single nucleotide polymorphisms (SNPs) in the bovine IGF-1 gene and alongside previously identified SNPs (2) determine their association with traits of economic importance in Holstein-Friesian dairy cattle. Nine novel SNPs were identified across a panel of 22 beef and dairy cattle by sequence analysis of the 5′ promoter, intronic, and 3′ regulatory regions, encompassing ~5 kb of IGF-1. Genotyping and associations with daughter performance for milk production, fertility, survival, and measures of body size were undertaken on 848 Holstein-Friesian AI sires. Using multiple regression analysis nominal associations (P < 0.05) were identified between six SNPs (four novel and two previously identified) and milk composition, survival, body condition score, and body size. The C allele of AF017143 a previously published SNP (C-512T) in the promoter region of IGF-1 predicted to introduce binding sites for transcription factors HSF1 and ZNF217 was associated (P < 0.05) with increased cow carcass weight (i.e., an indicator of mature cow size). Novel SNPs were identified in the 3′ region of IGF-1 were associated (P < 0.05) with functional survival and chest width. The remaining four SNPs, all located within introns of IGF-1 were associated (P < 0.05) with milk protein yield, milk fat yield, milk fat concentration, somatic cell score, carcass conformation, and carcass fat. Results of this study further demonstrate the multifaceted influences of IGF-1 on milk production and growth related traits in cattle.

Stage-specific developmental gene expression of goat preimplantation embryos produced in vitro

Single preimplantation embryo mRNA differential display was used to study the gene expression of 2-cell,4-cell, and 8-16-cell stage goat embryos produced in vitro, and 16 different stage specific bands in total were screened. In these specific bands, 5 were in 2-cell stage, 4 were in 4-cell stage, and 7 were in 8-16-cell stage, respectively. The sequencing and alignment results suggested that 4 differential expression bands were homologous with human petidylarginine deiminase (PAD), bovine insulin-like growth factor binding protein-3 (IGFBP3), bovine NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4 (NDUFA4), and dog cyclin B3 (CCNB3) genes, respectively. All these 4 genes had the functions on physiological regulation and were important factors in the process of goat preimplantation embryo development.

Single nucleotide polymorphisms at the imprinted bovine insulin-like growth factor 2 (IGF2) locus are associated with dairy performance in Irish Holstein-Friesian cattle

The imprinted insulin-like growth factor 2 gene (IGF2) encodes a fetal mitogenic hormone protein (IGF-II) and has previously been shown to be associated with performance in dairy cattle. In this study we assessed genotype-phenotype associations between four single nucleotide polymorphisms (SNPs) located within the bovine IGF2 locus on chromosome 29 and a range of performance traits related to milk production, animal growth and body size, fertility and progeny survival in 848 progeny-tested Irish Holstein-Friesian sires. Two of the four SNPs (rs42196909 and IGF2.g-3815A>G), which were in strong linkage disequilibrium (r2 = 0·995), were associated with milk yield (P ≤ 0·01) and milk protein yield (P ≤ 0·05); the rs42196901 SNP was also associated (P ≤ 0·05) with milk fat yield. Associations (P ≤ 0·05) with milk fat percentage and milk protein percentage were observed at the rs42196901 and IGF2.g-3815A>G SNPs, respectively. The rs42196909 and IGF2.g-3815A>G SNPs were also associated with progeny carcass conformation (P ≤ 0·05), while an association (P ≤ 0·01) with progeny carcass weight was observed at the rs42194733 SNP locus. None of the four SNPs were associated with body size, fertility and progeny survival. These findings support previous work which suggests that the IGF2 locus is an important biological regulator of milk production in dairy cattle and add to an accumulating body of research showing that imprinted genes influence many complex performance traits in cattle.

An association of C/T polymorphism in exon 2 of the bovine insulin-like growth factor 2 gene with meat production traits in Polish Holstein-Friesian cattle

The effect of the insulin-like growth factor 2 (IGF2) gene polymorphism &amp;ndash; a g.292C&amp;gt;T transition in exon 2 on feed uptake and conversion, growth rates, and meat production traits in Polish Holstein-Friesian cattle was investigated. A total of 291 young bulls were genotyped using restriction fragment length polymorphism (RFLP-BsrI). Animals were slaughtered at the age of 11 or 15 months and carcass traits were examined. At the age of 11 months the association was shown of the CC genotype with higher cold carcass weight, daily gain and meat content (%) in valuable cuts. At 15 months of age the CC genotype bulls showed higher live body weight, whereas those with the CT genotype had more fat in valuable cuts. The TT genotype bulls appeared to consume more feed (dry matter and protein) and used more feed for maintenance and meat production as compared to the CC genotype. The imprinting status of the IGF2 gene was analysed using cDNA sequencing and RFLP-BsrI. In 15-months-old animals and in foetuses older than two months both IGF2 alleles, maternal and paternal, were equally expressed in liver. In a 2-months-old male foetus the IGF2 mRNA was primarily expressed from the paternal allele. &amp;nbsp;

Sequence Variations in the Bovine IGF- I and IGFBP3 Genes and Their Association with Growth and Development Traits in Chinese Beef Cattle

The objective of this study was to determine the genotype effects of the bovine insulin-like growth factor I ( IGF- I) and its binding protein 3 ( IGFBP3) genes on growth and development traits in beef cows, including 130 Chinese Simmental, 42 Nanyang, and 47 Luxi Yellow cattle. Sequence variations in the bovine IGF- I and IGFBP3 genes were investigated by single strand conformation polymorphism (SSCP). SSCPs were detected in 6 fragments, which is the 5′-flanking region, the 2nd exon, the 5th exon, and the 5th intron of the IGF- I gene, and the 2nd exon, the 3rd exon of the IGFBP3 gene. Two polymorphisms, an A-to-G transition in the 2nd exon of the IGF- I gene and a T-to-C transition in the 2nd exon of IGFBP3 gene were detected in 3 breeds. The allele frequencies of 2 polymorphisms were 0.0411 (A), 0.9589 (B), and 0.7237 (A), 0.2763 (B), respectively. These 2 loci were analyzed to associate with body weight, height at withers, body length, heart girth, rump width, and beef production index (BPI) at 0, 6, 12, 24, and 36-month old. The IGFBP3 locus was shown to be associated with rump width, heart girth at 24-month and 36-month. Animals with BB genotype had higher rump width (24.86 ± 0.47) cm at 24-month and (27.50 ± 0.63) cm at 36-month. The heart girth was highest for the individuals with BB genotype (171.33 ± 1.84) cm and higher than those with AB genotype (166.68 ± 1.13) cm ( P < 0.05) at 36-month.