the structure found in the cell that contains strands of dna is called mitochondrial dna.
the structure found in the cell that contains strands of dna is called mitochondrial dna.
the structure found in the cell that contains strands of dna is called a(n)?
mitochondrial dna
cells of interest are cultured either in vivo or in vitro. during s-phase cells are treated with bromodeoxyuridine (brdu) which is then incorporated into their nascent dna, acting as a substitute for thymidine. after at least one replication event has occurred, the daughter cells are synchronized at the g2 phase and individually separated by fluorescence-activated cell sorting (facs). the cells are directly sorted into lysis buffer and their dna is extracted. having been arrested at a specified number of generations (usually one), the inheritance patterns of sister chromatids can be assessed. the following methods concentrate on the dna sequencing of a single daughter cell's dna. at this point the chromosomes are composed of nascent strands with brdu in place of thymidine and the original template strands are primed for dna sequencing library preparation. since this protocol was published in 2012, the canonical methodology is only well described for illumina sequencing platforms; the protocol could very easily be adapted for other sequencing platforms, depending on the application. next, the dna is incubated with a special dye such that when the brdu-dye complex is excited by uv light, nascent strands are nicked by photolysis. this process inhibits polymerase chain reaction (pcr) amplification of the nascent strand, allowing only the parental template strands to be amplified. library construction proceeds as normal for illumina paired-end sequencing. multiplexing pcr primers are then ligated to the pcr amplicons with hexamer barcodes identifying which cell each fragment they are derived from. unlike single cell sequencing protocols, strand-seq does not utilize multiple displacement amplification or malbac for dna amplification. rather, it is solely dependent on pcr.
single-cell dna template strand sequencing
the m6a methyltransferases (n-6 adenine-specific dna methylase) (a-mtase) are enzymes that specifically methylate the amino group at the c-6 position of adenines in dna. they are found in the three existing types of bacterial restriction-modification systems (in type i system the a-mtase is the product of the hsdm gene, and in type iii it is the product of the mod gene). these enzymes are responsible for the methylation of specific dna sequences in order to prevent the host from digesting its own genome via its restriction enzymes. these methylases have the same sequence specificity as their corresponding restriction enzymes. these enzymes contain a conserved motif asp/asn-pro-pro-tyr/phe in their n-terminal section, this conserved region could be involved in substrate binding or in the catalytic activity. the structure of n6-mtase taqi (m.taqi) has been resolved to 2.4 a. the molecule folds into 2 domains, an n-terminal catalytic domain, which contains the catalytic and cofactor binding sites, and comprises a central 9-stranded beta-sheet, surrounded by 5 helices; and a c-terminal dna recognition domain, which is formed by 4 small beta-sheets and 8 alpha-helices. the n- and c-terminal domains form a cleft that accommodates the dna substrate. a classification of n-mtases has been proposed, based on conserved motif (cm) arrangements. according to this classification, n6-mtases that have a dppy motif (cm ii) occurring after the fxgxg motif (cm i) are designated d12 class n6-adenine mtases. the type i restriction and modification system is composed of three polypeptides r, m and s. the m (hsdm) and s subunits together form a methyltransferase that methylates two adenine residues in complementary strands of a bipartite dna recognition sequence. in the presence of the r subunit, the complex can also act as an endonuclease, binding to the same target sequence but cutting the dna some distance from this site. whether the dna is cut or modified depends on the methylation state of the target sequence. when the target site is unmodified, the dna is cut. when the target site is hemimethylated, the complex acts as a maintenance methyltransferase, modifying the dna so that both strands become methylated. hsdm contains an alpha-helical domain at the n-terminus, the hsdm n-terminal domain.
dna methyltransferase