Journal of Animal Science

Reeds, P., J.

doi: 10.2527/1991.69suppl_31xpmid: N/A

Article PDF first page preview Close This content is only available as a PDF. Author notes 1 This work is a publication of the USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine and Texas Children's Hospital, Houston, TX. This projest has been funded in part with federal funds from the U.S. Department of Agriculture, Agricultural Research Service under Cooperative Agreement number 58-7MN1-6-100. The contents of this publication do not necessarily reflect the views or policies of the U.S. Department of Agricalture, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. The author is grateful to M. A. Fiorotto, R J. Schwartz, and T. A. Davis for many stimulating discussions and to J. Easrman for his editorial advice. 2 Dept. of Pediatrics. Copyright, 1991, The American Society of Animal Science

Simmen, Frank, A.

doi: 10.2527/1991.69suppl_324xpmid: N/A

Abstract The application of molecular biology to the study of animal growth has provided many important insights regarding the nature of regulatory proteins and their molecular sequence, structure, interactions, tissue expression, and physiologic regulation during growth. In many cases, the isolation of a growth-related gene precedes any knowledge of protein sequence or structure. In fact, protein sequences are now commonly determined by isolating (cloning) and sequencing the corresponding nuclear gene or messenger RNA(s) (complementary DNA). A variety of strategies and techniques are described for cloning and sequencing growth-related genes of interest These include use of antibodies, synthetic oligodeoxyribonucleotides, binding ligands, and restriction-fragment length polymorphisms for purposes of screening bacteriophage and plasmid clone libraries containing animal DNA molecules. Recombinant DNA technology is continually evolving, as evidenced by the impact of novel polymerase chain reaction methods for rapidly cloning and sequencing DNA. Elucidation of the molecular biology of somatic and cellular growth and differentiation is of fundamental importance. In addition, the continued isolation of growth genes from human and livestock genomes will provide the foundation for the application of biotechnology to enhance animal growth, development, and survival. This content is only available as a PDF. Author notes 2 The author thanks Rosalia C. M. Simmen and Fuller W. Bazer for critically reading this review and Cheryl Feinstein for assistance with figures. 3 Dairy Sci. Dept. Copyright, 1991, The American Society of Animal Science

Kopchick, John, J.;Chen, Wen, Y.

doi: 10.2527/2000.69suppl_338xpmid: N/A

Abstract Two altered bovine growth hormone (bGH) genes (pBGH-M1 and pBGH-M8) were generated by use of oligonucleotide-directed mutagenesis protocols to determine the importance of an amphiphilic α-helix (helix three) in bGH relative to growth-related biological activities. pBGH-M1 encodes the changes of Lys-112 to Leu and Lys-114 to Trp and was designed to increase the hydrophobic region of the amphiphilic α-helix. pBGH-M8 encodes the changes of Glu-117 to Leu, Gly-119 to Arg, and Ala-122 to Asp and was designed to maximize the amphiphilicity of the helix. Both plasmids were expressed in mouse L cells. Transgenic mice that expressed pBGH-M1 showed a phenotype of enhanced growth typical of wild type bGH transgenic mice. However, transgenic mice that expressed pBGH-M8 demonstrated a growth-suppressed phenotype. The degree of growth suppression in the mice was directly related to serum levels of the altered bGH molecule. This content is only available as a PDF. Author notes 2 To whom reprint requests should be addressed. 3 Dept. of Zoology, Mol. and Cell Biol. Program and Edison Anim. Biotech. Center. Copyright, 1991, The American Society of Animal Science

Pinkert, C., A.

doi: 10.2527/2000.69suppl_349xpmid: N/A

Abstract Transgenic livestock improvement programs hold the promise of rapidly achieving genetic enhancement in commercially important livestock species. These advancements were previously possible only through traditional long-term selective breeding practices or through chance mutation. Over the last 6 yr, transgenic farm animals carrying transferred growth hormone or metabolically related structural genes were created, although studies evaluating these animals demonstrate the effects of inadequate regulation of transgene expression. To date, improved phenotypic growth performance exclusive of deleterious side-effects was produced in transgenic mice, but not in transgenic livestock However, the potential of transgenic technology can be illustrated by recent swine experiments. An additional $1 billion annual return to U.S. swine producers is possible, should a 10% increase in feed efficiency and growth rate be feasible, as illustrated by exogenous porcine GH (pGH) treatments to pigs. Clearly, the incentive is great for genetic engineering of farm animals. Ongoing research continues to explore improvement of experimental protocols, the developmental regulation of transgenes, and the phenotypic consequences of mammalian gene transfer. This content is only available as a PDF. Author notes 1 The author gratefully acknowledges the invaluable assistance of M. Wieghart, J. L. Hoover, J. L. Sartin, D. J. Kiehm, M. J. Martin, V. G. Pursel and the Edison Animal Biotechnology Program. This work was supported in part by funds from USDA 87-CRSR-2-3223 and DNX, Inc. 2 Present address: Dept. of Comparative Med., Univ. of Alabama – Birmingham, 418 Volker Hall, Birmingham, AL 35294. Copyright, 1991, The American Society of Animal Science

Novakofski,, Jan

doi: 10.2527/1991.69suppl_356xpmid: N/A

Abstract Proto-oncogenes or cellular oncogenes are important in the normal regulation of growth. The potential for oncogenes to cause cancer if they become defective is a direct indication of their significance. Most oncogenes code for intracellular proteins involved in signal transduction pathways and represent closely related gene families. Several families of oncogenes, such as erbB, ros, and fms, are membrane receptors with tyrosine kinase activity. Oncogenes in the src family are also tyrosine kinases located in the membrane, but they function as a kinase subunit for an independent receptor. Signals are transduced by phosphorylation of intracellular substrates, which include phosphatidylinositol pathway kinases and cytoplasmic kinases. Signal transduction from membrane kinases may be modulated by the ras oncogenes, which are highly conserved GTP binding proteins located in the cell membrane. Oncogenes coding for nuclear proteins that bind DNA and may be phosphorylated by kinases such as raf or abl represent the final step in signal transduction. Formation of various dimers that have different effects on gene expression is an important characteristic of the regulation by DNA binding proteins. DNA binding proteins include helix-loop-helix proteins, such as the product of the myc oncogene or the MyoD, and myogenin genes that are involved in regulating muscle-specific genes, as well as leucine zipper proteins such as the fos or jun products. Cell growth is also controlled by anti-oncogenes, Rb and p53, that normally function to inhibit growth rather than to stimulate growth, as most proto-oncogenes do. This content is only available as a PDF. Author notes 1 Dept. of Anim. Sci., Muscle Biol. Lab. Copyright, 1991, The American Society of Animal Science

Frohman, Lawrence, A.

doi: 10.2527/1991.69suppl_374xpmid: N/A

Article PDF first page preview Close This content is only available as a PDF. Author notes 1 Studies in the author's laboratory were supported, in part by USPHS Grant DK 30667. 2 Div. of Endocrinol, and Metab., Dept. of Internal Med. Copyright, 1991, The American Society of Animal Science