RESUMEN
A recently reported Y receptor that has been confusingly referred to as both Y5 and Y2b has now been designated as Y6 by the IUPHAR organization. Using random primed Y6 coding sequence as a hybridization probe we examined the mRNA expression pattern and gene distribution of the Y6 receptor in a variety of species. We detail the relative abundance of Y6 message in mouse and human tissues and report the apparent absence of message for this receptor in any rat tissues tested. We also document the presence of the Y6 gene in chicken, rabbit, cow, dog, mouse, monkey and human, but the complete absence of the Y6 gene in rat.
Asunto(s)
Eliminación de Gen , Hipotálamo/metabolismo , Ratas/genética , Receptores de Neuropéptido Y/biosíntesis , Receptores de Neuropéptido Y/genética , Animales , Bovinos , Pollos , Perros , Femenino , Haplorrinos , Humanos , Masculino , Ratones , Especificidad de Órganos , ARN Mensajero/biosíntesis , Conejos , Especificidad de la Especie , Transcripción GenéticaRESUMEN
Chromosome fragmentation vectors (CFVs) are used to create deletion derivatives of large fragments of human DNA cloned as yeast artificial chromosomes (YACs). CFVs target insertion of a telomere sequence into the YAC via homologous recombination with Alu repetitive elements. This event results in the loss of all YAC sequences distal to the site of integration. A new series of CFVs has been developed. These vectors target fragmentation to both Alu and LINE human repetitive DNA elements. Recovery of deletion derivatives is ten- to 20-fold more efficient with the new vectors than with those described previously.
Asunto(s)
Cromosomas Fúngicos , Vectores Genéticos , Biblioteca de Genes , Genoma Humano , Humanos , Mapeo Restrictivo , Transformación GenéticaRESUMEN
Runs of adenines (adenine tracts) have been implicated as the main determinant of sequence-directed DNA bending. The most widely used experimental test for bending relies on the observation that bent DNA migrates more slowly than straight DNA on a polyacrylamide electrophoresis gel. It was shown recently that the polymer (GTTTTAAAAC)n runs with normal mobility on a gel, whereas (GAAAATTTTC)n runs more slowly and thus appears to be strongly bent. The observation that these similar sequences, which differ only in the order of the adenine and thymine tracts, adopt such different shapes offers a stringent test of theories to explain DNA bending. Although the wedge model for DNA bending has recently been elaborated to explain the gel mobilities of these molecules, we wished to determine experimentally the structural basis for the difference in bending. We report here measurements of the frequency of cleavage by the hydroxyl radical at each nucleotide of cloned versions of the two polymers (see Fig. 1). We show that the TTTTAAAA sequence does not display the cleavage pattern that is associated with bent DNA, whereas the AAAATTTT sequence does. The observed sequence dependence of the cleavage pattern of an adenine tract is at odds with current models for DNA bending, which assume that adenine tracts always adopt the same conformation.
Asunto(s)
Adenina , ADN , Conformación Molecular , Secuencia de BasesRESUMEN
To determine the structural features responsible for the curvature of kinetoplast DNA, we studied 13 adenine tracts in Crithidia fasciculata kinetoplast DNA. The structures of the A tracts were analyzed by cutting the DNA with hydroxyl radical. Reactivity of hydroxyl radical toward the DNA backbone progressively decreased in the 5'----3' direction of each A tract. The cutting pattern of the T-rich strand was offset by 1 or 2 bp from the pattern on the A-rich strand. An A tract in a restriction fragment from plasmid pBR322 had the same cutting pattern as the kinetoplast A tracts. We interpret these experiments to show that in A tracts the width of the minor groove decreases smoothly from the 5'----3' end of the A tract.