PIT-1基因在人、鼠及猪中的研究现状

本文对PIT-1基因在鼠、人及猪中作为生长发育性状候选基因的研究现状作-综述,主要包括PIT-1基因与鼠矮小性状、人类综合性垂体激素缺陷症及猪的生长和胴体性状之间的关系,并对PIT-1基因在小型猪中的研究前景作一展望。 This paper summaries the current study status of PIT-1 gene,which is the candidate gene for growth and development performance.The review mainly includes the association of PIT-1 gene with dwarfism in mice,CPHD in humans and growth and carcass traits in pigs.The research prospect of PIT-1 gene in mini-pig is also discussed.     

Analysis of associations of PIT1 genotypes with growth,meat quality and carcass composition traits in pigs

PIT1 was chosen as a candidate gene to investigate its associations with growth, meat quality and carcass composition traits in the pig. PIT1 is known as the pituitary-specific activator of the growth hormone in several mammals. Furthermore, PIT1 is a positive regulatory factor of prolactin and thyroid-stimulating hormone beta. PIT1 is a member of the POU-domain family of genes and is located on porcine chromosome 13. Two informative three-generation families of the University of Hohenheim were used for the presented investigations. The families were based on crosses of the European Wild boar (W) x Pietrain (P) and Meishan (M) x Pietrain (P). Each family included 310 F(2) animals. A RsaI (PCR) RFLP described by Yu et al. (1994) was used for genotyping the animals. Altogether over 50 parameters of growth, meat quality, carcass composition and stress susceptibility were evaluated concerning their associations with RsaI PCR-RFLP. The statistical model of association analyses was used including fixed effects of sex, family, PIT1 genotypes and covariate age at slaughter. Taking the significance level of p < 0.05 as the basis, fourteen traits of growth and carcass composition were associated with PIT1 genotypes in family W x P. Results from this study suggest that there are contributions of PIT1 gene to variations in the analysed performance traits in pigs. The influence of PIT1 genotypes could not be confirmed under the supposition of a genome-wide test limit.     

Association of corticotropin-releasing hormone gene variation with performance and meat quality traits in commercial pig lines

The porcine corticotropin-releasing hormone(CRH) gene is a functional-positional candidate for quantitative tract loci on porcine chromosome 4 with major effects on growth and carcass composition. In addition, the central role of CRH in the neuroendocrine response to stress implicates the CRH gene as a functional candidate for meat quality. Association of a single nucleotide polymorphism (SNP) in the promoter region of the porcine CRH gene (g.233C > T) with several growth, carcass and meat quality traits was examined using more than 2000 individuals from four commercial lines: German Landrace (LR), Pietrain (Pi), German Large White x German Landrace (F1) and the German commercial fattening pig cross of Pietrain x F1 (PiF1). Significant association of the CRH SNP was found with feed conversion ratio in the PiF1 line, with carcass length in the LR line and with lean content in the F1, LR and Pi lines. Moreover, significant association with meat colour was found in the Pi and LR lines; however, the effects were in opposite directions. The presented results indicate that sequence variation in the porcine CRH gene has no major effect on growth and carcass composition in commercial pig lines, although it may significantly contribute to variation in meat quality. The g.233C>T SNP may be in incomplete linkage disequilibrium with causal mutations and/or exhibit effects in the context of DNA variation at other interacting loci.     

猪ATF4基因多态性与生产性状的关联及基因表达分析

为进一步了解和认识ATF4基因的功能,揭示ATF4对猪脂肪代谢的影响,寻找与肉质性状相关联的分子标记,文章采用PCR方法扩增了ATF4基因部分序列,通过序列比对发现在翻译起始密码子ATG下游159 bp处存在A159G转换,通过PCR-AluⅠ-RFLP对大白猪、长白猪、梅山猪和通城猪进行酶切分型,发现在大白猪和长白猪中均为AA基因型,在梅山猪和通城猪中均为GG基因型。进一步对大白猪×梅山F2群体资源家系进行了酶切分型,并分析该位点的多态性与生产性状的关系。结果表明,ATF4的多态性与臀部平均膘厚存在极显著相关(P<0.01),与胸腰椎间膘厚、平均膘厚、眼肌高、眼肌面积存在显著相关(P<0.05)。采用Real-time PCR分析了ATF4基因在大白猪与梅山猪背最长肌不同发育阶段的表达模式。结果表明,ATF4基因在大白猪和梅山猪胚胎期65 d和出生后3 d中的表达水平相对都比较低,且在两品种间无明显差异;而在出生后60 d和120 d,ATF4基因在大白猪中与梅山猪均出现了上调表达,并且在梅山猪中的相对表达水平要显著高于大白猪。研究结果为进一步深入研究猪ATF4基因在脂肪代谢中的分子机理奠定了基础。     

猪FUT1基因对肉质和胴体性状的影响

测定139头杂交猪(大白猪和梅山猪)的14个肉质性状和8个胴体性状,用PCR-RFLP方法检测FUT1基因型。分析猪FUT1基因型间肉质和胴体性状差异,发现AA基因型猪3个部位肌肉pH值均比AG基因型的高,其中pH(LD)达到显著水平(P<0.05)。AA基因型猪肌肉系水力显著高于AG猪的系水力(91.02% VS 86.70%,P<0.05)。AA基因型猪的肉色值显著高于AG猪的(P<0.05)。AA基因型猪三个部位肌肉膘厚值均较低,其中最后肋骨膘厚和倒数三四肋骨膘厚分别比AG基因型猪的低4.26 mm和3.96 mm(P<0.05)。AA基因型猪瘦肉率比AG基因型猪的高3.31% (53.46% VS 50.15%,P<0.05)。以上结果表明FUT1基因的AA基因型对肉质和和胴体性状具有显著的正遗传效应,这对于在抗病育种中应用该基因十分有利。     

Polymorphisms and expression of the chicken POU1F1 gene associated with carcass traits

POU1F1 is an essential factor that regulates the development and reproduction of animal. The objective of the current research was to screen for polymorphism, expression of POU1F1 and their association with carcass quality traits. A total of 126 Erlang mountainous chickens from two strains (SD02 and SD03) were employed for testing. Seventeen single nucleotide polymorphisms (SNPs) were detected, but only two SNPs (g.96217999 T > C and g.96219442 C > T) were associated with carcass quality traits. In SD03 chicken, g.96217999 T > C genotypes were significantly associated with body weight (BW), carcass weight (CW), eviscerated weight (EW), and semi-eviscerated weight (SEW; P < 0.05), and was highly significantly associated with breast muscle weight (BMW) and abdominal fat weight (AW; P < 0.01). g.96219442 C > T was significantly associated with BW, EW, SEW (P < 0.05). However, these two SNPs were not significantly associated with any carcass traits in SD02 chicken. Diplotypes showed that in SD03 chicken, the haplotype [C: C] was the most favorable haplotype because it was associated with higher BW, CW, SEW, EW, BMW, and AW (P < 0.05). On the contrary, haplotype [T: T] was associated with lower carcass quality traits (P < 0.01). In addition, qRT-PCR revealed that at 13 weeks, the POU1F1 mRNA expression was significantly higher in breast muscle of cock compared to that of hens (P < 0.05), whereas there was no significant correlation between POU1F1 expression and carcass traits. These results suggested that POU1F1 could be a potential candidate gene for carcass traits in chicken.     

Association between polymorphisms of Myf5 and POU1F1 genes with growth and carcass traits in Hanwoo (Korean cattle)

Myogenic factor 5 (Myf5) and POU class 1 homeobox 1 (POU1F1) genes play important roles in growth and development of mammals. Bovine Myf5 and POU1F1 were characterized to detect genetic variation at these loci and to replace them to economic traits in 367 cattle representing Hanwoo (325) and Angus (37). Two single nucleotide polymorphisms (SNPs) were identified in intron 2 (A1948G SNP) of Myf5 and exon 6 (A15635G SNP) of POU1F1 by sequence analyses of genomic DNA. Statistical analysis indicated that the Myf5 polymorphisms significantly (0.05) associated backfat thickness and live weight at 6-months-of-age and that POU1F1 polymorphisms significantly influenced carcass weight and live weight at 24-month of age, and backfat thickness. The interaction between Myf5 and POU1F1 was significant on carcass weight, M. longissimus dorsi area, backfat thickness and marbling score. The results implicate Myf5 and POU1F1 as candidate genes of growth and carcass traits, and suggest that the interaction between Myf5 and POU1F1 strongly affect growth and carcass traits in cattle.     

Identification and characterization of a differentially expressed protein (CAPZB) in skeletal muscle between Meishan and Large White pigs

Actin capping protein beta (CAPZB) protein was identified with considerable differences in the longissimus dorsi muscle between Large White and Meishan pigs using proteomics approach. However, in pigs, the information on CAPZB is very limited. In this study, we cloned and characterized the porcine actin capping protein beta (CAPZB) gene. In addition, we present two novel porcine CAPZB splice variants CAPZB1 and CAPZB2. CAPZB1 was expressed in all twenty tissues. However, CAPZB2 was predominantly expressed in the skeletal muscle and heart. In addition, the two isoforms had different expression profiles during the skeletal muscle development and between breeds. Moreover, the SNP T394G was identified in the coding region of the CAPZB gene, which was significantly associated with the carcass traits including the LFW, CFW, SFT and LEA. Data presented in our study suggests that the CAPZB gene may be a candidate gene of meat production trait and provides useful information for further studies on its roles in porcine skeletal muscle.     

Association od the DdeI growth hormone gene polymorphism with some performance traits in Polish Large White and Czech Large White x Polish Large White pigs

The genotypes of growth hormone gene polymorphisms (GH-DdeI, GH-MspI, GH-HaeII, GH-ApaI, GH-CfoI) were determined in 78 pigs [Czech Large White sires (CLWsire line) x Polish Large White (PLW) sows, Polish Large White sires x Polish Large White sows], by the PCR-RFLP method. Preliminary studies found only GH DdeI polymorphism to be associated with performance traits. The associations of this polymorphism with growth and carcass traits were investigated. The linear model included the effects of candidate genes, genetic groups, sex and linear covariables of age at slaughter and body weight at weaning. The DdeI polymorphism of the GH gene showed associations with carcass length (P 相似文献   

Expression pattern, genomic cloning and RFLP analyses of the swine PIT-1 gene

The swine PIT-1 POU domain cDNA was used to study PIT-1 expression and to clone the PIT-1 genomic region to identify additional PIT-1 polymorphisms. PIT-1 was expressed only in the pituitary, confirming the swine cDNA identity. To study the PIT-1 genomic region, a clone containing 13.7 kb DNA was isolated. EcoRI fragments hybridizing to PIT-1 were sequenced, and the 3′ portion of PIT-1 gene identified. Primers for polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis were then designed. Restriction analysis of PCR products identified a RsaI RFLP. In contrast to other PIT-1 RFLPs, the RsaI PCR-RFLP was widely distributed in American breeds. Thus, the RsaI RFLP and the previously reported PIT-1 RFLPs allow detection of PIT-1 alleles in most, if not all, breeds currently used in the US and European reference/resource pig mapping families.     

Single nucleotide polymorphisms in chicken lmbr1 gene were associated with chicken growth and carcass traits

Lmbr1 is the key candidate gene controlling vertebrate limb development, but its effects on animal growth and carcass traits have never been reported. In this experiment, lmbr1 was taken as the candi-date gene affecting chicken growth and carcass traits. T/C and G/A mutations located in exon 16 and one A/C mutation located in intron 5 of chicken lmbr1 were detected from Silky, White Plymouth Rock broilers and their F2 crossing chickens by PCR-SSCP and sequencing methods. The analysis of vari-ance (ANOVA) results suggests that T/C polymorphism of exon 16 had significant association with eviscerated yield rate (EYR), gizzard rate (GR), shank and claw rate (SCR) and shank girth (SG); A/C polymorphism of intron 5 was significantly associated with SCR, liver rate and head-neck weight (HNW), while both sites had no significant association with other growth and carcass traits. These results demonstrate that lmbr1 gene could be a genetic locus or linked to a major gene significantly affecting these growth and carcass traits in chicken.