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In the bovine genome we found two intrachromosomal DNA fragments flanked by inverted telomeric repeats (GenBank Accession Nos. AF136741 and AF136742). The internal parts of the fragments are homologous exclusively to the human sequences and to the consensus sequence of the L1MC4 subfamily of LINE-1 retrotransposons which are widespread among mammalian genomes. We found that distribution of homologous human sequences within our fragments is not random, reflecting a complicated pattern of insertion mechanisms of and maintenance of retrotransposons in mammalian genomes. One of the possible explanations of the origin of LINE-1 truncated elements flanked by inverted telomeric repeats in the bovine genome is that extrachromosomal DNA fragments may be modified by telomerase and subsequently, transferred into chromosomal DNA.
The c-H-ras-1 gene of an B6C3F1 mouse was isolated and nucleotide sequence determined. Our study has revealed that this c-H-ras-1 gene consists of four exons, separated by three introns ranging in size from 150 to 649 bp. The coding parts of the sequence of mouse c-H-ras-1 gene show no important differences as compared with those of the rat, hamster and human gene. More numerous changes were found in introns. The identity of mouse c-H-ras-1 gene with rat, hamster and human ones at the nucleotide level is 86.40%, 80.04% and 67.87%, respectively. Comparison of amino acids in protein sequence of c-H-ras gene of mouse, rat, hamster and human points to high degree of conservation of the gene.
Boar seminal vesicle protein tyrosine acid phosphatase (PTAP) and human prostatic acid phosphatase (PAP) show high affinity for protein phosphotyrosine residues. The physico-chemical and kinetic properties of the boar and human enzymes are different. The main objective of this study was to establish the nucleotide sequence of cDNA encoding boar PTAP and compare it with that of human PAP cDNA. Also, the amino-acid sequence of boar PTAP was compared with the sequence of human PAP. PTAP was isolated from boar seminal vesicle fluid and sequenced. cDNA to boar seminal vesicle RNA was synthesized, amplified by PCR, cloned in E. coli and sequenced. The obtained N-terminal amino-acid sequence of boar PTAP showed 92% identity with the N-terminal amino-acid sequence of human PAP. The determined sequence of a 354 bp nucleotide fragment (GenBank accession number: GQ184596) showed 90% identity with the corresponding sequence of human PAP. On the basis of this sequence a 118 amino acid fragment of boar PTAP was predicted. This fragment showed 89% identity with the corresponding fragment of human PAP and had a similar hydropathy profile. The compared sequences differ in terms of their isoelectric points and amino-acid composition. This may explain the differences in substrate specificity and inhibitor resistance of boar PTAP and human PAP.
Autophagy is an important cellular process responsible for the maintenance of homeostasis in the mammary gland during its development and remodeling. The main function of autophagy is to degrade long-lived proteins and damaged organelles in double-membrane autophagic vacuoles containing hydrolytic enzymes. This process is also involved in the regulation of cell development and death. Three-dimensional (3D) cell cultures made it possible to recreate in vitro the process of alveoli formation by mammary epithelial cells (MECs). When cultured on extracellular matrix (ECM) components, MECs form 3D acini structures called mammospheres, composed of a single layer of polarized cells and a hollow lumen in the center of the acini. It has been shown that during the process of mammosphere formation, autophagy is induced in the centrally located cells in response to the stress related to their loss of contact with the ECM. Studies have shown that the induction of autophagy is augmented in the presence of sex steroids, which regulate cell survival during starvation conditions. Additionally, these hormones control the process of lumen formation, regulating the rate of apoptotic death in mammospheres. TGF-â1 also induces autophagy in 3D cultures, but the presence of this cytokine inhibits the development of acinar structures. On the other hand, IGF-I stimulates the growth of mammospheres, inducing autophagy in the numerous cells located in the centre of acinar structures, where the availability of nutrition is insufficient. The present review article describes some latest studies that point to the role of the close regulation of autophagy by endocrine and intramammary signals during mammogenesis.
The transgenic chicken has great potential as a bioreactor for the production of valuable pharmaceutical proteins, notably in the oviduct/egg. Whereas conventional transgenic approaches have significant limitations in this species, an alternative approach employing primordial germ cells (PGCs), the progenitor cells to ova and spermatozoa, has now been successfully applied to the insertion of exogenous genes into birds. Recent developments in manipulating avian embryos make it possible to produce germline chimeras derived from transferred PGCs. In this review we describe the migration pathway of chicken PGCs during early development. We then summarize different methods for the isolation of PGCs and the diversity of techniques used to introduce genes into these cells. Finally, we describe an in vitro assay for testing tissue-specific vectors designed to express heterologous proteins in transgenic chickens.
9-Aminoacridine carboxamide derivatives studied here form with DNA intercalative complexes which differ in the kinetics of dissociation. Inhibition of total RNA synthesis catalyzed by phage T7 and Escherichia coli DNA-dependent RNA polymerases correlates with the formation of slowly dissociating acridine-DNA complex of time constant of 0.4-2.3 s. Their effect on RNA synthesis is compared with other ligands which form with DNA stable complexes of different steric properties. T7 RNA polymerase is more sensitive to distamycin A and netropsin than the E. coli enzyme while less sensitive to actinomycin D. Actinomycin induces terminations in the transcript synthesized by T7 RNA polymerase. Despite low dissociation rates of DNA complexes with acridines and pyrrole antibiotics no drug dependent terminations are observed with these ligands.
A Polish strain of foot-and-mouth disease virus type О from the laboratory virus collection was used. The virus was propagated in BHK-21 monolayer cells. Total RNA was extracted by the Chomczyński and Sacchi method. A synthesis of cDNA was performed with AMV-reverse transcriptase. The first and second cDNA strands were used as a template for the amplification by PCR of the 672 bp of the VP1 coding sequence. The amplified fragment of cDNA was cloned in the phagemid pBS (+). The first DNA strand expressed in the phage M13K07 was sequenced according to the Sanger method. The nucleotide sequences were compared to the earlier data published. Genetic similarities to the Brasilian strain of FMDV O1 Campos 58 were found.
The aim of the studies was to determine the sex of cattle embryos by identifying Y-chromosome specific DNA sequence using the polymerase chain reaction (PCR). The sex of embryos fertilized in vitro and produced from the stage 2b up to hatched blastocyst was determined. Also the comparison of whole embryos and biopsed parts of them was performed. A total of 336 embryos was used. The sex of the embryos was determined with similar accurancy using a few biopsed cells as the whole embryo. The number of male and female embryos differed with the stage of development. In the stage of expanding blastocysts the ratio of male to female blastocysts was from 39.6% to 60.4% ( p s 0.5). In the group of hatched blastocysts the opposite situation was found, namely 62.5 % male and 37.5% female blastocysts (p s 0.01).
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