Control of rDNA replication in Tetrahymena involves a cis-acting upstream repeat of a promoter element

Larson, Drena D.; Blackburn, Elizabeth H.; Yaeger, Peter C.; Orias, Eduardo

doi:10.1016/0092-8674(86)90445-9

Cited by 119 publications

(161 citation statements)

References 34 publications

Supporting

Mentioning

151

Contrasting

Order By: Relevance

“…Ream (10,38) and for rDNA replication in Tetrahymena spp. (21) and has been suggested for the abnormal amplification of a human T-cell differentiation antigen (20). The different frequencies of amplification observed in independent clones transfected with selectable genes also point to the importance of cis-acting sequences (6,16,42).…”

Section: Discussionmentioning

confidence: 99%

Preferential amplification of rearranged sequences near amplified adenylate deaminase genes.

Debatisse¹,

Saito²,

Buttin³

et al. 1988

Mol. Cell. Biol.

View full text Add to dashboard Cite

In a previous study of three independent families of mutants selected for overproduction of adenylate deaminase (AMPD), we were not able to isolate a cDNA probe for the gene and so could not demonstrate its amplification directly. In addition to overproduction of AMPD, four proteins of unknown function, designated W, X, Y1, and Y2, accumulated, and by using the corresponding cDNA probes, we demonstrated amplification of anl four genes. In independent mutant clones, sometimes all and sometimes only a subset of these genes were amplified. Assuming that all five genes are linked, the pattern of their coamplification suggested a genetic map in which AMPD lies between W and Y1. We show here that a two-step chromosome walk joins the W and Y1 genes, that the AMPD gene is the only expressed sequence between them, and that its amplification is indeed responsible for overproduction of the AMPD protein. In the course of this work, we cloned and studied two novel joints which mark rearrangements on either side of the AMPD gene. Each joint was generated independently in a single first-step mutant at single or low copy number. Remarkably, each joint was amplified preferentially in every second-and third-step mutant derived from the first-step line in which it was originally present, suggesting that the two independent rearrangements each generated amplification-prone structures.In a number of systems, drug resistance is mediated by gene amplification, and in all cases studied, a sequence much larger than the selected gene is amplified. The first estimates of the average sizes of amplified units-defined as extra DNA sequences containing one copy of the selected geneindicate that they range from about 200 to 3,000 kilobases (kb) in highly resistant cells which have experienced several independent amplification events (for reviews, see references 18, 35, and 39). More recently, a study of the structures formed in the first step of amplification of the CAD gene in Syrian hamster cells has led to the hypothesis that, in this case, the average size of the amplified unit may be 10,000 kb or more (15).Several different techniques have been used to study the structure of the coamplified DNA: cloning of amplified sequences by differential screening (2,4,15) or from purified double minutes (5,14) or homogeneously staining regions (19,43), chromosome walking from the cloned selected genes (11,22), direct visualization of ethidium bromidestained amplified restriction fragments in agarose gels (24,40) and in gel renaturation (12, 31). In most cases, the results point to remarkable differences between the sequences coamplified in independent highly amplified mutants: the amplified units include a region comprising the selected gene and sequences immediately surrounding it in the wild-type line, but also include sequences which are amplified uniquely in each cell line (2,5,12, 34,36,43). Thus, during the amplification process, pieces of DNA from different parts of the genome are joined by recombination to form novel structures and novel join...

show abstract

Section: Discussionmentioning

confidence: 99%

Preferential amplification of rearranged sequences near amplified adenylate deaminase genes.

Debatisse¹,

Saito²,

Buttin³

et al. 1988

Mol. Cell. Biol.

View full text Add to dashboard Cite

show abstract

“…Evolutionarily conserved Type I repeat sequences have been implicated in the control of both replication and transcription of rDNA in Tetrahymena tliermophila (Larson et al, 1986: Miyahara et al, 1993. Previously, we reported the identification in Tetrahymena of a sequence-specific single-stranded DNA binding protein, ssA-TIBF.…”

Section: Discussionmentioning

confidence: 99%

“…Moreover, in wild-Type C3-rDNA. these sequences are identical for the Type lb and Ic repeats ( Figure 1C), and C3-rmm mutations that affect rDNA replication and/ or maintenance in the macronucleus are due to single base pair deletions within one of these two repeats (asterisks in Figure IB) (Larson et al. 1986;Yaeger et al, 1989 (Figure 3).…”

Section: Methodsmentioning

confidence: 99%

“…One major band was observed migrating as a polypeptide of 24 kDa (Figure 2 (Figure 1). This region was of special interest because it contains the determinant of the replication disadvantage of B-relative to C3-rDNA (Larson et al, 1986;Yaeger et al, 1989). Moreover, in wild-Type C3-rDNA.…”

Section: Methodsmentioning

confidence: 99%

“…1985;Niles et al, 1981). Asterisks denote Type I elements altered in C3-rmm mutants defective in rDNA replication and/or maintenance in the macronucleus (Larson et al, 1986;Yaeger et al, 1989 (Yao. 1986;Kapler.…”

mentioning

confidence: 99%

See 2 more Smart Citations

A single-stranded DNA binding protein that specifically recognizes cis-acting sequences in the replication origin and transcriptional promoter region of Tetrahymena rDNA

Hou

Umthun²,

Dobbs³

1995

Biochemistry

View full text Add to dashboard Cite

show abstract

On the nature of origins of DNA replication in eukaryotes

1992

Self Cite

View full text Add to dashboard Cite

Chromosomal origins of DNA replication in higher eukaryotes differ significantly from those of E. coli (oriC) and the tumor virus, SV40 (ori sequence). Initiation events appear to occur throughout broad zones rather than at specific origin sequences. Analysis of four chromosomal origin regions reveals that they share common modular sequence elements. These include DNA unwinding elements, pyrimidine tracts that may serve as strong DNA polymerase-primase start sites, scaffold associated regions, transcriptional regulatory sequences, and, possibly, initiator protein binding sites and inherently destabilized regions. Based on the novel organization of chromosomal origin regions, we propose a model for initiation of DNA replication in higher eukaryotes. Unwinding of duplex DNA during initiation may be uncoupled, both temporally and spatially, from DNA synthesis, resulting in transient single-stranded intermediates that function in lieu of conventional replication forks during chromosomal DNA replication. DNA synthesis begins subsequently at multiple sites within the unwound regions rather than at specific origin sequences.

show abstract

Control of rDNA replication in Tetrahymena involves a cis-acting upstream repeat of a promoter element

Cited by 119 publications

References 34 publications

Preferential amplification of rearranged sequences near amplified adenylate deaminase genes.

Preferential amplification of rearranged sequences near amplified adenylate deaminase genes.

A single-stranded DNA binding protein that specifically recognizes cis-acting sequences in the replication origin and transcriptional promoter region of Tetrahymena rDNA

On the nature of origins of DNA replication in eukaryotes

Contact Info

Product

Resources

About