In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

The culture conditions found to result in stable proliferation of normal rat hepatocytes are: (i) subconfluent cell densities; (ii) serum-free medium; (Wi) hormonally defined medium containing epidermal growth factor, insulin, glucagon, prolactin, and other growth factors; and (iv) substrata of liver extracellular matrix depleted of growth inhibitors. Serum was found deleterious to parenchymal cells: it was inhibitory to the expression of liver-specific functions, cytostatic to parenchymal cells at all seeding densities, and cytotoxic to them at low seeding densities. These studies emphasize the relevance of synergies in the influences of hormones and extracellular matrix in regulating hepatocellular physiology.Past efforts to produce long-term proliferation of adult hepatocytes in culture have met with limited success (1-8 Substrata. Cells were plated on one of the following substrata: (i) Tissue culture plastic. Sixty-millimeter tissue culture dishes (Falcon). (ii) Type I collagen gels. Sixty-millimeter tissue culture dishes (Falcon) were coated with type I collagen gels prepared from rat tail tendons (10). (ifi) Normal rat liver biomatrix. Livers from normal Sprague-Dawley rats were utilized to prepare biomatrix by the methods of Reid (12). The biomatrix was pulverized into a fine powder with a Spex-Mill liquid nitrogen pulverizer (Spex-Mills, Metuchen, NJ), thickly smeared onto 60-mm Petri dishes (Falcon) and then sterilized by 'y irradiation (cesium-135) at 10,000 rads (100 grays). Just before use, the plates were rinsed with serum-free RPMI 1640 medium supplemented with penicillin at 200 units/ml and streptomycin at 200 pug/ml. (iv) Rat regenerating liver biomatrix. Five days after partial hepatectomy (18), livers were used for biomatrix preparation (12). (v) Normal rat liver biomatrix prepared by low-salt extraction. Biomatrix from normal rat liver was prepared by extracting the tissue with 1.0 M NaCl and omitting the initial wash in distilled water, prepared as described (11).Morphological Studies. Cultures of hepatocytes were plated under various conditions and maintained for 1-2 weeks. They were examined by using a Nikon inverted phase-contrast microscope. Cultures were evaluated by a number of investigators independently. Representative cultures were selected and photographed with phase-contrast microscopy.[3H]Thymidine Incorporation. At 1411The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Tropomyosins are a closely related family of proteins with a dimeric alpha-coiled-coil structure. Skeletal isoforms are composed of two types of subunits, alpha and beta which, in turn, are assorted into two main molecular species alpha alpha and alpha beta. Both isoforms are present in different molar ratios in individual skeletal muscle types. In small mammals, however, only alpha-chain is expressed in cardiac muscle. Tropomyosin, in association with the troponin complex (troponin-I, -T and -C) plays a central role in the Ca2+-dependent regulation of vertebrate striated muscle contraction. On the other hand, despite structural similarities with the striated isoforms, the function of this protein in smooth muscle and non-muscle cells remains unknown, because in these cells contraction is thought to be regulated by myosin-linked processes independently of tropomyosin. Here we report the nucleotide sequences of cloned complementary DNAs for rat striated and smooth muscle alpha-tropomyosin. Comparison of the derived amino-acid sequences reveals the existence of tissue-specific peptides that delimit the putative troponin-I and troponin-T binding domains of tropomyosin. S1-nuclease mapping studies reveal the existence of three distinct alpha-tropomyosin messenger RNA isoforms each encoding a different protein; these isoforms are tissue-specific, developmentally regulated and most probably encoded by the same gene.

Abstract. We have characterized cDNAs coding for three Na,K-ATPase tx subunit isoforms from the rat, a species resistant to ouabain. Northern blot and Sl-nuclease mapping analyses revealed that these a subunit mRNAs are expressed in a tissue-specific and developmentally regulated fashion. The mRNA for the al isoform, --~-4.5 kb long, is expressed in all fetal and adult rat tissues examined. The a2 mRNA, also ---4.5 kb long, is expressed predominantly in brain and fetal heart. The ix3 cDNA detected two mRNA species: a ---4.5 kb mRNA present in most tissues and a ---6 kb mRNA, found only in fetal brain, adult brain, heart, and skeletal muscle. The deduced amino acid sequences of these isoforms are highly conserved. However, significant differences in codon usage and patterns of genomic DNA hybridization indicate that the a subunits are encoded by a multigene family. Structural analysis of the a subunits from rat and other species predicts a polytopic protein with seven membranespanning regions. Isoform diversity of the a subunit may provide a biochemical basis for Na,K-ATPase functional diversity.

The acceleration of atherosclerosis by polygenic (essential) hypertension is well-characterized in humans; however, the lack of an animal model that simulates human disease hinders the elucidation of pathogenic mechanisms. We report here a transgenic atherosclerosis-polygenic hypertension model in Dahl salt-sensitive hypertensive rats that overexpress the human cholesteryl ester transfer protein (Tg[hCETP]DS). Male Tg[hCETP]DS rats fed regular rat chow showed age-dependent severe combined hyperlipidemia, atherosclerotic lesions, myocardial infarctions and decreased survival. These findings differ from various mouse atherosclerosis models, demonstrating the necessity of complex disease modeling in different species. The data demonstrate that cholesteryl ester transfer protein can be proatherogenic. The interaction of polygenic hypertension and hyperlipidemia in the pathogenesis of atherosclerosis in Tg[hCETP]DS rats substantiates epidemiological observations in humans.

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Despite the prevalence of essential hypertension, its underlying genetic basis has not been elucidated due to the complexities of its determinants. To identify a hypertension susceptibility gene, we used an approach that integrates molecular, transgenic, and genetic analysis using

The molecular recognition theory suggests that binding sites of interacting proteins, for example, peptide hormone and its receptor binding site, were originally encoded by and evolved from complementary strands of genomic DNA. To test this theory, we screened a rat kidney complementary DNA library twice: first with the angiotensin II (AII) followed by the vasopressin (AVP) antisense oligonucleotide probe, expecting to isolate cDNA clones of the respective receptors. Surprisingly, the identical cDNA clone was isolated twice independently. Structural analysis revealed a single receptor polypeptide with seven predicted transmembrane regions, distinct AII and AVP putative binding domains, a Gs protein-activation motif, and an internalization recognition sequence. Functional analysis revealed specific binding to both AII and AVP as well as AII- and AVP-induced coupling to the adenylate cyclase second messenger system. Site-directed mutagenesis of the predicted AII binding domain obliterates AII binding but preserves AVP binding. This corroborates the dual nature of the receptor and provides direct molecular genetic evidence for the molecular recognition theory.