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Biomedical subjects

J M Espinosa-Lara

Publications and source records attributed to J M Espinosa-Lara.

2 recordsLinked to original sources

Gene synthesis technology: recent developments and future prospects.

Gene synthesis is a potentially powerful tool in molecular biology that has not yet reached widespread use because of the relatively high cost and labor-intensive nature of the process. This paper reviews some recent technological developments and current research activities of this laboratory which promise to greatly reduce the cost of gene synthesis and to increase the speed and efficiency of the process. We recently developed an improved device for "segmented" synthesis of oligonucleotides, which utilizes porous Teflon wafers containing derivatized controlled pore glass supports to simultaneously synthesize up to 100 different DNA sequences. The stepwise coupling efficiency with the "wafer synthesis device" is as high as that attained with current automated "gene machines" producing 1-4 oligonucleotides at a time, whereas the reagent usage is only 20-50% that of the current DNA synthesizers. At present, we are optimizing the conditions for rapid, efficient assembly of genes on a solid-phase support, wherein ordered, stepwise annealing/washing is performed to segmentally elongate a "starting" oligonucleotide attached to a solid-phase support. We expect that the wafer synthesis device (operated at reduced scale of synthesis), together with solid-phase gene assembly, will permit the synthesis and assembly of an average size gene (1 kb) in one week at a cost of less than $1000. These developments should make gene synthesis a routine and powerful tool in molecular biology.

Biotechnology↗

Rat DNA polymerase beta substitutes the repairing activity of DNA polymerase I in the lethal effect of UV light.

The aim of this work was to search if the rat DNA polymerase beta can substitute the capability of DNA polymerase I to repair damage caused by the UV light in Escherichia coli. The oriC origin of replication from p beta 5 was replaced by the rep origin from pSC101 and named p beta 6. The presence of pol beta in the new construct was verified by PCR. E. coli polA-1 (WP6) was transformed with p beta 6. A protein with size similar to DNA Pol beta (40 kDa) was shown in the cell free extracts carrying pbeta5. In WP6/p beta 6 cell free extracts a slightly smaller protein was observed instead of the 40 kDa. DNA Pol beta was revealed by western analysis, with polyclonal antibodies, in strains with p beta 5. Yet, it was not detected in the western from WP6/p beta 6. A moderate change in UV resistance was observed in strains carrying p beta 5. However, in polAl carrying p beta 6 (WP6/p beta 6), irradiated with 60-90 J/m2 of UV light, the viability was increased by more than four orders of magnitude, when compared with the polA1 (WP6) strain, reaching approximately the same UV resistance as the strains with DNA polymerase I. The results suggests that probably Pol beta is rapidly degraded in the cell free extracts from WP6/p beta 6 and, it repairs the lethal effect of the UV light in E. coli.

Animals↗