Cloning and nucleotide sequencing of the bovine growth hormone gene

Evaluation of candidate genotype of GH gene associated with growth, production and reproduction traits in Dairy Cows

Growth hormone (GH) is a major regulator of postnatal growth and metabolism in mammals and plays a critical role in growth, production and fertility in cattle. The present study was conducted in dairy cattle to find the association of g.48769565 C>T mutation with growth, production and reproduction traits in Sahiwal and Hardhenu cattle. PCR-RFLP was performed to genotype g.48769565 C>T mutation using the MspI restriction enzyme in our resource cattle population. In Hardhenu cattle, the frequencies of C and T alleles were 0.59 and 0.41 respectively while genotypic frequencies were 0.06, 0.36 and 0.58 for CC,CT and TT respectively. The frequencies of the C and T allele were 0.24 and 0.76 respectively in Sahiwal cattle and it was observed that highest frequency was forTT genotype (0.58) and lowest for CC genotype (0.06). Chi-square analysis showed that g.48769565C>T SNP loci did not meet with the Hardy-Weinberg equilibrium (p< 0.01) in Sahiwal cattle. From the least-squares analysis, it was observed that CC genotype was significantly associated with total Milk Yield (TMY), 300 days milk yield (300D MY), lactation length (LL), Dry period (DP) and Artificial insemination (AI)/conception (p<0.05). We also observed a significant association (p<0.05) of genotype CT with 3-month calves body weight. Cows with TT genotype revealed comparatively revealed favourable service period (SP) and calving interval (CI) in both Hardhenu and Sahiwal. These observed differences in their allelic and genotypic frequencies in association with the traitsunderlying production and fertility can be utilized for genetic improvement in dairy cattle.

Effects of Lactobacillus casei Strain T2 (IBRC-M10783) on the Modulation of Th17/Treg and Evaluation of miR-155, miR-25, and IDO-1 Expression in a Cuprizone-Induced C57BL/6 Mouse Model of Demyelination

Multiple sclerosis (MS) is a complex inflammatory disease in which demyelination occurs in the central nervous system affecting approximately 2.5 million people worldwide. Recent reports have shown that the gut microbiome plays a crucial role in the functioning of the immune system in inflammatory diseases such as MS. In this study, the cuprizone-induced demyelination mouse model was used to investigate the effect of Lactobacillus casei strain T2 (IBRC-M10783) on the alleviation of these mice. Female C57BL/6 mice (8-10 weeks old) were divided into 6 groups: group 1, normal control; group 2, cuprizone control (oral administration of cuprizone 0.2% w/w for 4 weeks); group 3, probiotic control (oral administration of 1 × 10⁹ CFU/ml probiotic for 4 weeks); group 4, treatment 1 (probiotic for 4 weeks then cuprizone for 4 weeks); group 5, treatment 2 (cuprizone for 4 weeks then probiotic for 4 weeks); and group 6, treatment 3 (cuprizone for 4 weeks then probiotic for 4 weeks with vitamin D₃ at a dose of 20 IU/day). Then, TGF-β and IL-17 were measured by ELISA, and the expression of miR-155, miR-25, and IDO-1 was evaluated by real-time PCR. Among the measured microRNAs, the results showed that there was a significant decrease in miR-155 expression between the treatment 1 group and the cuprizone group. In the case of IL-17, the results also showed a significant reduction between the three treatment groups and the cuprizone group. These observations suggest that L. casei can reduce proinflammatory cytokines and reduce demyelinating symptoms in the mouse model.

Aging progression of human gut microbiota

Background

Human gut microbiota are important for human health and have been regarded as a “forgotten organ”, whose variation is closely linked with various factors, such as host genetics, diet, pathological conditions and external environment. The diversity of human gut microbiota has been correlated with aging, which was characterized by different abundance of bacteria in various age groups. In the literature, most of the previous studies of age-related gut microbiota changes focused on individual species in the gut community with supervised methods. Here, we aimed to examine the underlying aging progression of the human gut microbial community from an unsupervised perspective.

Results

We obtained raw 16S rRNA sequencing data of subjects ranging from newborns to centenarians from a previous study, and summarized the data into a relative abundance matrix of genera in all the samples. Without using the age information of samples, we applied an unsupervised algorithm to recapitulate the underlying aging progression of microbial community from hosts in different age groups and identify genera associated to this progression. Literature review of these identified genera indicated that for individuals with advanced ages, some beneficial genera are lost while some genera related with inflammation and cancer increase.

Conclusions

The multivariate unsupervised analysis here revealed the existence of a continuous aging progression of human gut microbiota along with the host aging process. The identified genera associated to this aging process are meaningful for designing probiotics to maintain the gut microbiota to resemble a young age, which hopefully will lead to positive impact on human health, especially for individuals in advanced age groups.

Identification of Single Nucleotide Polymorphisms (SNPs) of the Bovine Growth Hormone (bGH) Gene Associated with Growth and Carcass Traits in Hanwoo

The purpose of this study was to find any association of the bovine growth hormone (bGH) gene with growth and carcass quality traits in Korean native cattle, Hanwoo. Genomic DNA was extracted from 21 Hanwoo individuals, and the 47 to 2,528 bp region of the bGH 2,856 bp (GenBank accession number M57764) including the promoter and the five exons was sequenced. A total of ten bGH SNPs were confirmed, including four (253 C>T, 303 C>T, 502 C>T, and 559 G>A) in the promoter, one (679 C>T) in exon 1, one (1,692 T>C) in intron 3, and four (2141 C>G, 2258 C>T, 2277 C>T, and 2291 A>C) in exon 5. The ten bGH SNPs were genotyped for a sample of 242 Hanwoo steers and association tests were performed to find any significant SNP that was correlated with growth and carcass quality. Of the SNPs, the 303 C>T SNP in the promoter region was significantly associated with 6-month-old weight, the 559 G>A SNP with longissimus dorsi muscle area, the 2141 C>G SNP in exon 5 with daily weight gain, and the 2258 C>T SNP with daily weight gain and carcass weight (p<0.05). The significant SNPs need to be verified in other Hanwoo populations before considering implementation of marker-assisted selection for genetic improvement of growth and carcass quality in Hanwoo.

Analysis of genetic variation in the Belgian Blue cattle breed using DNA sequence polymorphism at the growth hormone, low density lipoprotein receptor, alpha-subunit of glycoprotein hormones and thyroglobulin loci

New DNA sequence polymorphisms were identified at four bovine autosomal loci: growth hormone, low density lipoprotein receptor, alpha-subunit of glycoprotein hormones and thyroglobulin. Assuming independent assortment between these polymorphisms, the probabilities to be heterozygous at these four loci are 0.48, 0.36, 0.10 and 0.77 respectively, within the Belgian Blue Cattle breed (BBCB). Nucleotide diversity was estimated, showing that animals from the BBCB are heterozygous for 1/1450 nucleotides, a value significantly lower than the 1/500 value found in man. Moreover, we have estimated that the mutation rate at the cytosines of CG dinucleotides is about 10 times higher than that for other nucleotides.

Restriction fragment length polymorphisms in dairy and beef cattle at the growth hormone and prolactin loci

Two bovine populations, a Holstein-Friesian dairy stock and a synthetic (Baladi X Hereford X Simmental X Charolais) beef stock, were screened for restriction fragment length polymorphisms (RFLPs) at the growth hormone and prolactin genes. Most RFLPs at the growth hormone gene are apparently the consequence of an insertion/deletion event which was localized to a region downstream of the structural gene. The restriction map for the genomic region including the growth hormone gene was extended. Two HindIII RFLPs at the growth hormone locus, as well as several RFLPs at the prolactin gene, seemed to be the consequence of a series of point mutations. The results are discussed in terms of the possibility that minor genomic variability underlies quantitative genetic variation.

The bovine gene map

The present status of the bovine gene map as well as some of the methods and strategies important for future efforts in completing the gene map of cattle are reviewed.

Restriction fragment length polymorphisms associated with growth hormone and prolactin genes in Holstein bulls: evidence for a novel growth hormone allele

Sperm DNA isolated from sons of three extensively used US Holstein bulls was screened for differences associated with the primary gene structure of the bovine growth hormone (bGH) and prolactin (bPrl) genes. Southern blot analysis of DNA digested with 10 restriction enzymes revealed that offspring from two of the three bull families exhibited polymorphisms around the bGH and bPrl genes. Restriction fragment length polymorphisms (RFLPs) around the bGH gene were detected with five enzymes, whereas three enzymes revealed RFLPs around the bPrl gene. At least three structural differences were predicted around the bGH gene. The most common variant hybridization pattern appeared to involve an insertion/deletion located downstream of the conserved 3' EcoRI site. The presence of RFLPs in the genes coding for these pituitary hormones within a familial line may provide the basis for genetic markers associated with lactation and mammary development.

Gene structure and functional characterization of growth hormone in dogfish, Squalus acanthias

Dogfish (Squalus acanthias) growth hormone (GH) was identified by cDNA cloning and protein purification from the pituitary gland. Dogfish GH cDNA encoded a prehormone of 210 amino acids (aa). Sequence analysis of purified GH revealed that the prehormone is composed of a signal peptide of 27 aa and a mature protein of 183 aa. Dogfish GH showed 94% sequence identity with blue shark GH, and also showed 37-66%, 26%, and 48-67% sequence identity with GH from osteichtyes, an agnathan, and tetrapods. The site of production was identified through immunocytochemistry to be cells of the proximal pars distalis of the pituitary gland. Dogfish GH stimulates both insulin-like growth factor-I and II mRNA levels in dogfish liver in vitro. The dogfish GH gene consisted of five exons and four introns, the same as in lamprey, teleosts such as cypriniforms and siluriforms, and tetrapods. The 5'-flanking region within 1082 bp of the transcription start site contained consensus sequences for the TATA box, Pit-1/GHF-1, CRE, TRE, and ERE. These results show that the endocrine mechanism for growth stimulation by the GH-IGF axis was established at an early stage of vertebrate evolution, and that the 5-exon-type gene organization might reflect the structure of the ancestral gene for the GH gene family.

Relationship of the bovine growth hormone gene to carcass traits in Japanese black cattle

The bovine growth hormone gene (bGH) possesses three haplotypes, A, B and C, that differ by amino acid mutations at positions 127 and 172 in the fifth exon: (leucine 127, threonine 172), (valine 127, threonine 172) and (valine 127, methionine 172) respectively. The correlation between meat quality or carcass weight and these haplotypes was investigated in Japanese black cattle. Altogether, 940 bGH haplotypes were compared with respect to six carcass traits: carcass weight, longissimus muscle area, rib thickness, subcutaneous fat thickness, beef marbling score and beef colour. The frequency of the B haplotype was higher (0.421) than that of A (0.269) and C (0.311). High carcass weight and low beef marbling were associated with haplotype A (p < 0.05 and p < 0.01 respectively), whereas beef marbling was increased by haplotype C (p < 0.05). Estimated regression coefficient of the A haplotype substitution effect for carcass weight and beef marbling score were 5.55 (13.1% of the phenotypic SD) and -0.31 (17.0%) respectively. That of the C haplotype for beef marbling score was 0.20 (11.0%). The other traits showed no relationship to the haplotypes examined. The results of this investigation suggest that information pertaining to bGH polymorphisms in Japanese black cattle could be used to improve the selection of meat traits.

Production of recombinant mink growth hormone in E. coli

Escherichia coli cells expressing mink (Mustela vison) growth hormone were grown in a batch fermentation process. The expression level was estimated to be 27% of the total cellular protein after 3 h of induction with 1 mM isopropyl beta-D-thiogalactoside (IPTG). If the expression of mink growth hormone (mGH) was induced with 0.2 mM IPTG, the concentration of target protein was slightly lower and was found to be 23% at the same time after induction. mGH expressed as inclusion bodies was solubilized in 8 M urea and renatured by dilution protocol at a protein concentration of 1.4-2.1 mg/ml in the presence of glutathione pair in a final concentration of 11.3 mM. [GSH]/[GSSG] ratio equal to 2/1 was used. Two-step purification process comprising of ion-exchange chromatography on Q-Sepharose and hydrophobic chromatography on Phenyl-Sepharose was developed. Some 25-30 mg of highly purified and biologically active mGH was obtained from 4 g of biomass. The method presented in this study allows producing large quantities of mGH and considering initiation of scientific investigation on mGH effect on mink in vivo and availability in fur industry.

Association of genetic polymorphism in GH gene with milk production traits in Beijing Holstein cows

Associations were analysed between polymorphisms of the growth hormone gene (GH-MspI) (localized in intron 3) and milk production traits of Beijing Holstein cows (a total of 543 cows). Polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method was used for identification of various genotypes. Frequencies of genotypes were 0.77, 0.21 and 0.02 for A/A, A/B and B/B, respectively. The frequency of the GH A allele is 0.875. The results of the least squares means show that in all three lactations, the GH A/A cows yielded more milk (P less than 0.01 for lactation I and P less than 0.05 for lactations II and III), whereas A/B cows showed higher milk fat content than A/A individuals (P less than 0.05 for lactations I and II, and P less than 0.01 for lactation III). The A/A cows yielded more fat than A/B individuals (P less than 0.01 only in lactation I). The A/A cows yielded more milk protein than A/B individuals (P less than 0.01 for lactations I, II, and III). The A/A cows produced milk of higher protein content than of A/B individuals (P less than 0.05 only in lactation II).

Genomic structure of the sea lamprey growth hormone-encoding gene

Growth hormone (GH) belongs to a family of pituitary hormones together with prolactin and somatolactin. In our previous study, GH and its cDNA were identified in the pituitary gland of the sea lamprey, Petromyzon marinus, an extant representative of the most ancient class of vertebrates, and isolated GH stimulated expression of insulin-like growth factor in the liver. The evidence suggests that GH is the ancestral hormone in the molecular evolution of the GH/PRL/SL family and that the endocrine mechanism for growth stimulation was established at an early stage in the evolution of vertebrates. To further understand the molecular evolution of the GH/PRL/SL gene family, we report the genomic structure of sea lamprey GH including its 5'-flanking region, being cloned by PCR using specific primers prepared from its cDNA. The sea lamprey GH gene consists of 13,604 bp, making it the largest of all the GH genes. The 5'-flanking region within 697 bp contains consensus sequences for a TATA box, two Pit-1/GHF-1, three TRE, and a CRE. The sea lamprey GH gene consists of five exons and four introns, the same as in mammals, birds, and teleosts such as cypriniforms and siluriforms with the exception of some teleosts such as salmoniforms, percififorms, and tetradontiforms, in which there is an additional intron in the 5th exon. The 5-exon-type gene organization might reflect the structure of the ancestral gene for the GH/PRL/SL gene family.

Polymorphism of the growth hormone gene of red deer (Cervus elaphus)

In mammals, pituitary growth hormone (GH) is usually encoded by a single gene, but in some caprine ruminants there are two GH genes, and higher primates have a cluster of at least 5 GH-like genes. We have previously shown that in several artiodactyls (chevrotain, giraffe, and hippopotamus) there are two GH gene sequences, differing by 5-21 nucleotides (nt), but whether these arise from two distinct gene loci is unclear. We report here that in the red deer (Cervus elaphus) also there are two main GH gene sequences (designated A and B) differing at about 23 nt. Investigation of DNA from a number of individual animals demonstrated that this variation was due to allelic polymorphism, with individuals carrying either the A-type or the B-type sequence, or both. A- and B-type sequences showed some variation between individuals. The overall difference between the A and B sequences is substantial-greater than that between the GH gene sequences of three distinct bovine species, Bos taurus (ox), Bos indicus (zebu) and Bos grunniens (yak). The biological significance of the presence of two markedly differing GH gene sequences in red deer is not clear, but it is notable that several of the differences between the A and B sequences occur in the 5' upstream region, which may be associated with differences in gene expression.

Placental hormones and fetal–placental development

Production of growth promoting substances by the placenta is regulated differently from the way production of similar compounds is regulated by maternal organs in various cases. Gene duplication is one of the mechanisms that facilitated the evolution of placental specific endocrine activity. Cattle, sheep and goats, although evolutionarily related, differ significantly from each other in the way their placental growth hormone (GH) and prolactin (PRL)-like hormones have evolved. Cattle carry one copy of the GH gene and there is no evidence yet for expression of that single GH gene copy in the placenta. On the other hand, the ovine GH gene has been duplicated and both oGH copies are expressed in the placenta during early stages of gestation. Prolactin gene duplication in ruminants resulted in the formation of specific placental-expressed prolactin-related genes including the placental lactogen (PL) gene. In homologous state, ovine PL manifests PRL activity, but antagonizes GH activity. Ovine PL activity which can be mediated by PRL receptors or by hetero-dimerization of GH and PRL receptors, provide a novel regulatory mechanism for somatogenic activity dependent on the coexistence of both GH and PRL receptors in the same cells. Another mechanism for specific placental endocrine activity is silencing of the alleles through genetic imprinting. Disruption of genetic imprinting of placental genes has been proposed as one of the explanations for the loss of cloned fetuses generated by somatic cell nuclear transfer.

Expression of the bovine growth hormone alters the root morphology in transgenic tobacco plants

The bovine growth hormone (bGH) is a natural peptide hormone that controls the differentiation, growth and metabolism, and is produced in the pituitary gland of cows. For the production of bGH from plants, two different bgh clones, of which the pGAbGH1 contaions only mature peptide sequences and the pGAbGH15 contains signal sequences and the first intron, as well as mature peptide sequences, were used. Those bghs under the control of the CaMV 35S promoter and NOS terminator were introduced to tobacco plants via Agrobacterium tumefaciens-mediated transformation. By PCR analyses using bgh and nptII specific primers, 17 and 21 putative transformants were respectively selected from pGAbGH1- and pGAbGH15-transformed tobacco plants. Northern blot analysis showed that the most of the transgenic lines expressed the bgh mRNA. Western blot analysis revealed that the pGAbGH1-transformed tobaccos produced recombinant bGH, but pGAbGH15-transformed ones did not produce the protein. Interestingly, some morphological changes were observed in the roots of transgenic tobacco plants. The transgenic tobacco plants had thick and short roots containing few root hairs in contrast to the non-transformed wild type plants.

Polymorphism in the bovine growth hormone gene affects endocrine release in dairy calves

The objective was to test whether calves with the Leu/Leu genotype release more growth hormone (GH) than calves with Leu/Val and Val/Val genotypes. Danish Holstein (n = 286), Danish Red (n = 68), and Danish Jersey (n = 61) calves were genotyped for the Leu/Val polymorphism in the GH gene and assessed for GH release following inducement by the growth hormone releasing hormone (GHRH). Three GH traits were assessed for each calf: BASELINE, PEAK, and RATE. BASELINE and PEAK are the mean concentration of GH in blood sampled before and after GHRH inducement. RATE is the disappearance rate of GH in blood sampled after GHRH inducement. Danish Jersey calves with Leu/Leu genotype had a higher PEAK and RATE than calves with the Val/Val genotype, whereas the Leu/Val genotype had an intermediate response. The contribution of the Leu/Val polymorphism to the total genetic variation of the BASELINE, PEAK, and RATE traits was 5, 30, and 27%, respectively. By contrast, the amount of GH released by the Danish Holstein and Danish Red calves was not influenced by their GH genotype. Further studies involving calves with all three genotypes are required to further elucidate whether this polymorphism has a functional role or whether it works through a linked-gene effect specific to certain cattle breeds.

Molecular evolution of growth hormone (GH) in Cetartiodactyla: cloning and characterization of the gene encoding GH from a primitive ruminant, the chevrotain (Tragulus javanicus)

In mammals the sequence of pituitary growth hormone (GH) is generally strongly conserved, indicating a slow basal rate of molecular evolution. However, on two occasions, during the evolution of primates and that of cetartiodactyls, the rate of evolution has increased dramatically (25 to 50-fold) so that the sequences of human and ruminant GHs differ markedly from those of other mammalian GHs. To define further the burst of GH evolution that occurred in cetartiodactyls, the GH gene of the chevrotain (Tragulus javanicus) has been cloned and characterized by use of genomic DNA and a polymerase chain reaction technique. Two very similar gene sequences, which probably reflect allelic variation, were isolated. The deduced sequence for the mature chevrotain GH differs from that of the bovine or red deer GH at only two to three residues, and phylogenetic analysis shows that the burst of rapid evolution of GH that occurred in the Cetartiodactyla must have been completed before the divergence of the Tragulidae and the advanced ruminants (Pecora). The rate of evolution during this burst must therefore have been greater than previously estimated. In other aspects (including signal sequence, 5' upstream sequence, and synonymous substitutions in the coding sequence), the chevrotain GH gene differs considerably from the GH genes of other ruminants and here there is no evidence for the period of accelerated evolution that is seen for GH itself.

The lac operator-repressor system is functional in the mouse

We report the successful transfer of a fully functional lac operator-repressor gene regulatory system to the mouse. The key component is a lac repressor transgene that resembles a typical mammalian gene both in codon usage and structure and expresses functional levels of repressor protein in the animal. We used the repressor to regulate the expression of a mammalian reporter gene consisting of the tyrosinase promoter embedded with three short lac operator sequences and the tyrosinase coding sequence. Pigmentation of the mouse was controlled by the interaction of the lac repressor with the regulatable Tyrosinase transgene in a manner that was fully reversible by the lactose analog IPTG. Direct control of mammalian promoters by the lac repressor provides tight, reversible regulation, predictable levels of de-repressed expression, and the promise of reversible control of the endogenous genome.

Genomic growth hormone gene polymorphisms in native Chinese chickens

Chicken growth hormone (cGH), a polypeptide hormone synthesized in and secreted by the pituitary gland, is involved in a wide variety of physiological functions such as growth, body composition, egg production, aging, and reproduction. Chicken growth hormone polymorphisms have been reported to be associated with certain phenotypes. Our objective is to investigate the GH gene polymorphism in selected strains of native Chinese chickens. Yellow Wai Chow GH gene was characterized by sequencing and was found to have one silent substitution, 31 insertions, and other substitutions spread among the introns. In addition, a novel Mspl site has been identified and characterized in the first intron. Allele frequencies of the intron 1 polymorphism were characterized among 28 populations of native Chinese chickens. Thus, polymorphism of the cGH gene may be useful in phylogenetic analysis, as well as in the design of breeding programs.

A new strategy in design of +RNA virus infectious clones enabling their stable propagation in E. coli

Infectious clone methodology is a valuable tool of modern experimental virology. However, its use is often constrained by the instability of infectious clone constructs during propagation in E. coli. To circumvent this problem, we have devised a strategy that could be suitable for design of +RNA virus molecular clones in general. An infectious clone is assembled as "infectious DNA," and expression of problem regions present in the viral cDNA is prevented during propagation in E. coli by insertion of short introns. To demonstrate the feasibility of this approach, a highly unstable Japanese encephalitis flavivirus infectious clone has been successfully converted into a remarkably stable infectious DNA construct with the specific infectivity of 10(6) pfu/microg in cell culture. The proposed strategy may be useful in the design of self-amplifying gene therapy vectors and development of new immunization methodologies, and could facilitate creation of molecular repositories of existing viral vaccines.

Genomic structure and sequence of the gilthead seabream (Sparus aurata) growth hormone-encoding gene: identification of minisatellite polymorphism in intron I

The growth hormone (GH) gene of the gilthead seabream (Sparus aurata) (saGH) has been cloned, sequenced, and characterized. The saGH gene spans approximately 4.3 kb and consists of six exons and five introns, as found for all cloned teleost GH genes with the exception of carps and catfish. The first and third introns contain long stretches of repetitive tandem repeats. The second intron, which is unusually long compared with that in other teleosts (and other vertebrates) spans 1747 nucleotides (nt) and contains several inverted repeats. Intron-targeted polymerase chain reaction (PCR) analysis identified length polymorphism of the first intron. Sequence analysis of four variants (405, 424, 636, and 720 nt) out of many variants found revealed that the variation in length is due to differences in the number of repeat monomers (17-mer or 15-mer) as well as minor changes in their length. This repeat unit contains the consensus half-site motif of the thyroid hormone response element (TRE) and estrogen response element (ERE). Polymorphism was found also in the third intron. This is the first report of such high polymorphism of the first intron of GH gene in a vertebrate.

cDNA cloning and sequence analysis of bubaline growth hormone

The cDNA for Bubalus bubalis growth hormone (GH) has been cloned and sequence determined through RT-PCR approach. The nucleotide sequence of bubaline GH cDNA was in a single reading frame coding for a protein of 191 residues comprising a putative signal sequence of 27 amino acids. Homology comparison of the sequence with other mammalian GH cDNAs showed a very high degree of evolutionary conservation. Bubaline GH sequence shared a homology of 99.5%, 99.5%, 98.6%, 87.6% and 61.9% with that of ovine, caprine, bovine, porcine and human, respectively at amino acid level.

Association of growth hormone loci with milk yield traits in Holstein bulls

A pedigree analysis was used to investigate the association of bovine growth hormone loci with milk production traits of Holstein cattle. Holstein bulls were typed for three bovine growth hormone loci located in exon V, intron C, and the 3' region of the gene. Phenotypic data were daughter yield deviations for milk, fat, and protein yields and for fat and protein percentages. Analysis of linkage across families was applied to the data using one or two bovine growth hormone loci as markers linked to a putative biallelic quantitative trait locus. Estimated parameters were allele frequency, genotypic means, within-genotype standard deviation of a putative quantitative trait locus, and recombination fraction between the markers and the quantitative trait locus. Parameters were estimated by maximum likelihood techniques. The estimated frequency of the quantitative trait locus allele that decreased the value of the phenotype ranged from 0.1 for milk yield to 0.6 for protein yield. The estimated effect of an allele substitution at the quantitative trait locus, given in phenotypic standard deviation units, ranged from 0.75 for fat percentage to 1.6 for milk yield. The standard deviation within genotype ranged from 0.67 for fat yield to 0.87 for milk yield. The estimated recombination fraction was close to zero for protein percentage, indicating physical linkage between a quantitative trait locus affecting the trait and the bovine growth hormone loci.

SR proteins are sufficient for exon bridging across an intron

We have developed a defined system to characterize the role of SR proteins and exonic enhancers in directly promoting splice-site interactions across an intron. Using RNA affinity chromatography, we find that SR proteins alone are sufficient to promote the specific association of the enhancer-containing exon 5 with the adjoining exon 6 from avian cardiac troponin-T. Direct visualization of this exon/exon association by electron spectroscopic imaging shows it to be highly specific. Furthermore, using in vivo characterized mutants of exon 5, we also show that this exon/exon association depends on the splicing enhancer within exon 5. These results suggest a model by which SR proteins may function through exonic enhancers to directly promote exon bridging.

Activation of the lac repressor in the transgenic mouse

We have introduced sequences encoding the lac repressor of Escherichia coli into the genome of the mouse. One sequence was derived from the bacterial lac operon and the other was created by re-encoding the amino acid sequence of lacI with mammalian codons. Both versions are driven by an identical promoter fragment derived from the human beta-actin locus and were microinjected into genetically identical pronuclear stage embryos. All transgenes utilizing the bacterial coding sequence were transcriptionally silent in all somatic tissues tested. The sequence re-encoded with mammalian codons was transcriptionally active at all transgene loci and expressed ubiquitously. Using methylation-sensitive enzymes, we have determined the methylation status of lac repressor transgenes encoded by either the bacterial or mammalian sequence. The highly divergent bacterial sequence was hypermethylated at all transgene loci, while the mammalian sequence was only hypermethylated at a high copy number locus. This may reflect a normal process that protects the genome from acquiring new material that has an abnormally divergent sequence or structure.

Transcriptional activation of the human growth hormone gene by ras oncogene

ras Oncogenes play an important role in causing cellular transformation and proliferation. They have been implicated in the formation of many human tumors but only rarely been identified in pituitary adenomas. We studied the effect of ras activation on growth hormone (GH) production. Transcriptional regulation of human GH was investigated by transient transfections in a pituitary cell line GH4 using different promoter fragments cloned 5' of the luciferase reporter gene (-344 to -83). Co-transfection of the constitutively active valine 12 mutant ras oncogene (V-12 ras) resulted in a selective and dose-dependent stimulation of -344-GH/Luc activity. This effect is pituitary-cell specific as activation of the human GH promoter by ras was absent in a human chorion carcinoma cell line JEG3. Co-transfection of protein kinase inhibitor did not influence ras mediated stimulation of the human GH promoter. Investigations of several deletion constructs of the human GH promoter revealed that elements between - 145 and - 83 are sufficient to transduce ras signaling. This region contains two Pit-1 bindings sites as well as a Zn-15 binding site. These studies demonstrate transduction of ras signaling to the human GH promoter through a protein kinase A (PKA) independent signaling pathway. This separate transduction mechanism may convey regulation by yet unknown factors.

The effects of a duplication in the ovine growth hormone (GH) gene on GH expression in the pituitaries of ram lambs from lean and fat-selected sheep lines

Growth hormone (GH) gene expression was investigated in pituitaries of 14- to 15-month-old ram lambs from flocks selected for high (fat) or low (lean) back fat depth, which were also homozygous for a single GH gene allele, heterozygous or homozygous for a duplication in the GH gene. The pituitaries of lean sheep of all three GH genotypes were significantly heavier than those of fat sheep, but there were no pituitary weight differences between GH genotypes. No significant lean-fat selection line- or GH genotype-specific differences were measured in pituitary GH concentration. However there was a significant increase (P < 0.01) in the total pituitary content of GH in lean compared with fat animals and a significant interaction between GH genotype and lean-fat selection line (P < 0.05) was noted for GH content. No significant differences were measured in the relative concentration of GH mRNA, suggesting that the ratio of GH mRNA per mg total cellular RNA remained constant across lean-fat selection line and GH genotype. We conclude that the pituitary glands of Coopworth sheep selected for low backfat depth (lean) are bigger and have an increased GH content, but appear to contain similar concentrations of GH mRNA and immunoreactive GH as the pituitaries of fat sheep. The presence of the GH gene duplication in sheep has little measurable effect on the expression and storage of GH in the pituitary.

Sequence variations in the bovine growth hormone gene characterized by single-strand conformation polymorphism (SSCP) analysis and their association with milk production traits in Holsteins

Sequence variations in the bovine growth hormone (GH) gene were investigated by single strand conformation polymorphism (SSCP) analysis of seven amplified fragments covering almost the entire gene (2.7 kb). SSCPs were detected in four of these fragments and a total of six polymorphisms were found in a sample of 128 Holstein bulls. Two polymorphisms, a T-->C transition in the third intron (designated GH4.1) and an A-->C transversion in the fifth exon (designated GH6.2), were shown to be associated with milk production traits. GH4.1c/GH4.1c bulls had higher milk yield than GH4.1c/GH4.1t (P < or = 0.005) and GH4.1t/GH4.1t (P < or = 0.0022) bulls. GH4.1c/GH4.1c bulls had higher kg fat (P < or = 0.0076) and protein (P < or = 0.0018) than GH4.1c/GH4.1t bulls. Similar effects on milk production traits with the GH6.2 polymorphism were observed with the GH6.2a allele being the favorable allele. The average effects of the gene substitution for GH4.1 and GH6.2 are similar, with +/-300 kg for milk yield, +/-8 kg for fat content and +/-7 kg for protein content per lactation. The positive association of GH4.1c and GH6.2a with milk production traits may be useful for improving milk performance in dairy cattle.

Cloning and characterisation of the rabbit growth hormone-encoding gene

The gene encoding growth hormone (GH) has been cloned from a rabbit genomic library, and its sequence has been determined. The rabbit GH gene is similar to other mammalian GH, being comprised of five exons and four introns. As in rodents and artiodactyls, the rabbit GH occurs as a single gene, with no evidence for a cluster of GH-like genes, as is found in primates. The amino acid sequence of rabbit GH is similar to that of pig GH and other conserved mammalian GH, and, like these, differs markedly from the available sequences of ruminant and primate GH. This provides further support for the idea that, in mammals, GH show a slow underlying rate of evolution which has increased markedly on at least two occasions.

Isolation and characterization of the functional gene encoding bovine cytochrome c oxidase subunit IV

The structure and expression of the gene (COX4) encoding bovine cytochrome c oxidase subunit IV (COX IV) was studied in order to identify conserved DNA sequence elements involved in the control of mammalian nuclear respiratory genes. The functional bovine COX4 gene consists of five exons and four introns and is similar in organization to rat and mouse COX4. The domain encoded by exon 3 is the most highly conserved among the three species, suggesting it may encode a key functional domain of COX IV. Transcription of bovine COX4 begins at multiple sites, as has been seen previously for rat and mouse COX4 and other TATA-less genes. Comparative analysis of bovine, rat and mouse COX4 promoters identified multiple binding sites for the regulatory proteins Sp1 and GABP (NRF-2). The varied arrangements of multiple Sp1 and GABP sites in mammalian COX4 promoters suggests flexibility in the positioning of regulatory factors in controlling COX4 expression.

Methylation and expression of a metallothionein promoter ovine growth hormone fusion gene (MToGH1) in transgenic mice

We have examined transgene methylation in the DNA from the livers of a pedigree of mice carrying three copies of an integrated MToGH1 transgene. Utilizing the methylation-sensitive isoschizomers Msp I and Hpa II, Southern blot analysis revealed that all second generation animals derived from a transgenic female had hypermethylated DNA, whereas first generation animals sired by a transgenic male displayed a range of methylation phenotypes ranging from no methylation to hypermethylation of the transgene sequences. Of the mice that exhibited hypermethylation of the transgene in CpG dinucleotides (CmCGG), a minority of these animals also exhibited apparent CpC methylation (i.e. inhibition of Msp I cutting, presumably blocked by methylation of the outer C of CCGG). Methylation was also examined in the inner C of CC(A/T)GG sequences in the MToGH1 transgene using the isoschizomer pair BstN I and EcoR II. A minority of MToGH1 animals in the F1 generation showed clear evidence of methylation in these sites as well as in the inner and outer Cs of CCGG sites. An examination of MToGH1 expression in terms of oGH levels in serum revealed that there was a high degree of variation in the levels of circulating oGH between animals of this pedigree. There was a weak inverse relationship between the serum level of oGH and the extent of methylation of the transgene. In particular, mice exhibiting CpC together with CpG methylation were found to have very low levels of circulating oGH. Our results highlight the nature and complexity of epigenetic factors associated with transgene sequences which may ultimately influence expression of introduced genes in the mammalian genome.

Primary sequence and functional analysis of the bovine galanin gene promoter in human neuroblastoma cells

Galanin (GAL) is a biologically active neuropeptide that has been suggested to play a role in stress-induced inhibition of insulin secretion, in dementia of the Alzheimer's type, and in the regulation of growth hormone secretion. We report here the isolation of a bovine genomic clone containing more than 5-kb 5'-flanking sequences. Partial sequence analysis of the genomic clone revealed an atypical TATA-box in the promoter (ATAAATA) and several consensus sequences that typically bind transcription factors, including those that bind NF kappa B, Sp1, and AP-2. Primer extension and RNase protection analyses revealed that transcription is initiated at two sites, 28 and 31 bp, respectively, downstream from the TATA-box. To locate functionally active regulatory elements on the GAL gene, we first identified a neural crest-derived human neuroblastoma cell line, SK-N-SH subclone SH-SY5Y, that expressed easily detectable levels of endogenous GAL mRNA. We then constructed plasmids containing various lengths of bovine GAL 5'-flanking sequences and the first exon fused to a reporter plasmid encoding luciferase. Transfection of these plasmids into the SH-SY5Y cells and analysis by transient expression indicated that 131 bp of 5' gene sequence was sufficient to obtain maximal basal expression. Further, expression was suppressed 16-fold when 5 kb were included, suggesting the presence of a distal repressor element(s). In another set of experiments, we found that GAL mRNA levels could be induced more than 10-fold by 20-hr treatment with phorbol 12-myristate 13-acetate (PMA). In cells transfected with the same plasmids, luciferase activity was also induced by PMA, but the degree of induction did not significantly differ among the deletion constructions (varying from six- to eight-fold), suggesting that elements conferring PMA induction and/or RNA stabilization may be located within 131 bp of the transcriptional start site, in the first exon, or on gene sequences not studied here.

A dog growth hormone cDNA codes for a mature protein identical to pig growth hormone

Although methods for purification of dog (Canis familiaris) growth hormone (cfGH) were described in the late Sixties, the cloning of its cDNA has not been achieved until now. In order to clone the cfGH cDNA, we capitalized on the high degree of nucleotide sequence conservation among mammalian GH genes to design a pair of consensus oligodeoxyribonucleotide primers. With these, and starting with dog pituitary gland total RNA, we specifically amplified the cfGH cDNA using the reverse transcription-polymerase chain reaction. Its coding sequence (651 bp), as well as its 3' untranslated region (101 bp), resemble those of a typical mammalian GH cDNA. Interestingly, its encoded mature protein is identical to pig growth hormone (pGH).

Variable evolutionary rates in the molecular evolution of mammalian growth hormones

In mammals pituitary growth hormone (GH) shows a slow basal rate of evolution (0.22 +/- 0.03 x 10(-9) substitutions/amino acid site/year) which appears to have increased by at least 25-50-fold on two occasions, during the evolution of primates (to at least 10.8 +/- 1.3 x 10(-9) substitutions/amino acid site/year) and artiodactyl ruminants (to at least 5.6 +/- 1.3 x 10(-9) substitutions/amino acid site/year). That these rate increases are real, and not due to inadvertent comparison of nonorthologous genes, was established by showing that features of the GH gene sequences that are not expressed as mature hormone do not show corresponding changes in evolutionary rate. Thus, analysis of non-synonymous substitutions in the coding sequence for the mature protein confirmed the rate increases seen in the primate and ruminant GHs, but analysis of nonsynonymous substitutions in the signal peptide sequence, synonymous substitutions in the coding sequence for signal peptide or mature protein, and 5' and 3' untranslated sequences showed no statistically significant changes in evolutionary rate. Evidence that the increases in evolutionary rate are probably due to positive selection is provided by the observation that in the cases of both ruminant and primate GHs the periods of rapid evolution were followed by a return to a slow rate similar to the basal rate seen in other mammalian GHs.(ABSTRACT TRUNCATED AT 250 WORDS)

Variants of somatotropin in cattle: gene frequencies in major dairy breeds and associated milk production

The amino acid sequence of bovine somatotropin (bST) varies at position 127 where either valine or leucine is found. The frequencies of leucine127 and valine127 bST gene alleles in cows (n = 302) and sires (n = 70) from major dairy breeds (Holstein, Brown Swiss, Guernsey, Jersey, and Ayrshire) were determined using DNA extracted from whole blood or spermatozoa. A 428 base pair fragment of the bST gene was amplified using polymerase chain reaction (PCR) and variants of the bST gene were detected as polymorphisms by Alu I restriction endonuclease digestion of PCR products. Restriction enzyme DNA fragments for the leucine127 variant were 265, 96, 51, and 16 base pair and for the valine127 variant were 265, 147, and 16 base pair as a polymorphism of bST was present in the 147 base pair DNA fragment. Frequencies of leucine127 and valine127 alleles for cows (n = 302) were 1.0 and 0 for Brown Swiss, .93 and .07 for Holstein, .92 and .08 for Guernsey, .79 and .21 for Ayrshire, and .56 and .44 for Jersey, respectively. In Holstein sires used for artificial insemination (n = 70), the frequency of leucine127 and valine127 alleles was .96 and .04. Estimates of transmitting ability for milk production tended to be greater for Holstein cows that were homozygous for leucine127 bST and Jersey cows that were homozygous for valine127 bST whereas Holstein sires with different bST genotypes were similar. In summary, frequencies of alleles for the bST gene were not similar in different dairy breeds and estimates of milk production were correlated with bST gene variant in cows but not sires.