Table of Contents Bacterial Artificial Chromosomes Cloning Components in Bacterial Artificial Chromosomes Mechanism Method Application
Cloning Bacterial Artificial Chromosomes(BAC) utilize a cloning system derived from a plasmid found in E.coli . Allows one to develop much larger pieces of DNA compared to standard plasmids (10,000bp vs 350,000bp) Reduces numbers of clones need to sequence a genome by 35x First used by Hiroaki Shizuya in 1992
Components in a bac RepE : for plasmid replication and regulation of copy number Hind III and Bam HI : Sites of Cloning oriS : The origin of replication CmR : Chloramphenicol resistance gene, selection tool ParA,ParB,ParC : the genes that regulate the partitioning of plasmids to daughter cells during division.
Mechanism Developed by taking parts of of the F’ and turning it into a vector. The origin of replication allows the host cell to recognize the new DNA insert. Location of HindiII and BAmHI within LacZ changes X-gal metabolism when target DNS is incorporated CmR induces antibiotic resistance to target DNA containing vectors
Vector and donor DNA both cut by same restriction enzyme Fragments are mixed and sticky ends hybridize via H-bonds DNA Ligase seals gaps by forming phosphodiester linages
Method DNA Fragments of interest are isolated and cleaved using restriction enzymes The BAC is digested by restriction enzymes around the cloning site ( HindlII and BamHI ) Recombinant DNA is formed ( F’plasmid and target DNA) using DNA ligase. New recombinant DNA is inserted into compliant cells and plated
Method As bacterial cells grow and divide they also amplify the BAC DNA which can be isolated CmR and LacZ distinguish between successful transmission of target gene into bacterium.
Applications BACs allow cloning and maintenance of large segments of DNA, making them useful in whole genome mapping Independent Chromosome allows easy isolation, and pure inserts. Allows genetic information to be stored from organisms that aren’t easily grown in cultures. Study of large pathogenic viruses
References W.C. Nierman , T.V. Feldblyum , in Encyclopedia of Genetics, 2001 G.M. Weinstock, in Encyclopedia of Genetics, 2001 “What Are BAC Libraries?” Facts , The Public Engagement Team at the Wellcome Genome Campus, 25 Feb. 2015 ,. StudiousGuy . “Cloning Vectors: Types & Characteristics.” StudiousGuy , StudiousGuy , 19 Sept. 2018, studiousguy.com /cloning-vectors-types-characteristics/. Kevinshe . “THE BIG BAD BAC: BACTERIAL ARTIFICIAL CHROMOSOMES.” SCQ , 6 Sept. 2006, www.scq.ubc.ca /the-big-bad-bac-bacterial-artificial-chromosomes/.