Molecular cloning of a rat chromosome putative recombinogenic sequence homologous to the hepatitis B virus encapsidation signal.

Previously, we reported that a 61-bp subgenomic HBV DNA sequence (designated as 15AB, nt 1855-1915) is a hot spot for genomic recombination and that a cellular protein binding to 15AB may be the putative recombinogenic protein. In the present study, we established the existence of a 15AB-like sequence in human and rat chromosomal DNA by Southern blot analysis. The 15AB-like sequence isolated from the rat chromosome demonstrated a 80.9% identity with 5'-CCAAGCTGTGCCTTGGGTGGC-3', at 1872-1892 of the hepatitis B virus genome, thought to be the essential region for recombination. Interestingly, this 15AB-like sequence also contained the pentanucleotide motifs GCTGG and CCAGC as an inverted repeat, part of the chi known hot spot for recombination in Escherichia coli. Importantly, a portion of the 15AB-like sequence is homologous (82.1%, 23/28 bp) to break point clusters of the human promyelocytic leukemia (PML) gene, characterized by a translocation [t(15;17)], and to rearranged mouse DNA for the immunoglobulin kappa light chain. Moreover, 15AB and 15AB-like sequences have striking homologies (12/15 = 80.0% and 13/15 = 86.7%, respectively) to the consensus sequence for topoisomerase II. Our present results suggest that this 15AB-like sequence in the rat genome might be a recombinogenic candidate triggering genomic instability in carcinogenesis.

Reduced fetal growth rate and increased risk of death from ischaemic heart disease: cohort study of 15 000 Swedish men and women born 1915-29

Objective: To establish whether fetal growth rate (as distinct from size at birth) is associated with mortality from ischaemic heart disease.

Grs 1915+105: a superluminal source in the Galaxy.

We present the results of additional observations of the high energy source GRS 1915+105, which produces ejecta with apparent superluminal motions. The observations reported here were carried out with the Very Large Array at 3.5 cm and 20 cm. The 3.5-cm observations made during 1994 May allowed us to continue following the proper motions of the bright 1994 March 19 ejecta, as well as those of a subsequent, fainter ejection. The proper motions of the 1994 March 19 ejecta continued to be ballistic (i.e., constant) over the period of about 75 days where they remained detectable. From the observations in 1994 March-May we have identified three ejections of pairs of plasma clouds moving ballistically in approximately the same direction on the sky with similar proper motions. The 20-cm observations made during 1994 November and December were used to search, yet unsuccessfully, for extended jets or lobes associated with GRS 1915+105.