A fully integrated microdevice and process for forensic short tandem repeat (STR) analysis has been developed that includes sequence-specific DNA template purification, polymerase chain reaction (PCR), post-PCR cleanup and inline injection, and capillary electrophoresis (CE). Fragmented genomic DNA is hybridized with biotin-labeled capture oligos and pumped through a fluidized bed of magnetically immobilized streptavidin-coated beads in microchannels where the target DNA is bound to the beads. The bead-DNA conjugates are then transferred into a 250 nL PCR reactor for autosomal STR amplification using one biotin and one fluorescence-labeled primer. The resulting biotin-labeled PCR products are electrophoretically injected through a streptavidin-modified capture gel where they are captured to form a concentrated and purified injection plug. The thermally released sample plug is injected into a 14 cm long CE column for fragment separation and detection. The DNA template capture efficiency provided by the on-chip sequence-specific template purification is determined to be 5.4% using K562 standard DNA. This system can produce full 9-plex STR profiles from 2.5 ng input standard DNA and obtain STR profiles from oral swabs in about 3 hours. This fully integrated microsystem with sample-in-answer-out capability is a significant advance in the development of rapid, sensitive, and reliable micro-total analysis systems for on-site human identification.

The Caenorhabditis elegans vitellogenin genes are subject to sex-, stage-, and tissue-specific regulation: they are expressed solely in the adult hermaphrodite intestine. Comparative sequence analysis of the DNA immediately upstream of these genes revealed the presence of two repeated heptameric elements, vit promoter element 1 (VPE1) and VPE2. VPE1 has the consensus sequence TGTCAAT, while VPE2, CTGATAA, shares the recognition sequence of the GATA family of transcription factors. We report here a functional analysis of the VPEs within the 5'-flanking region of the vit-2 gene using stable transgenic lines. The 247 upstream bp containing the VPEs was sufficient for high-level, regulated expression. Furthermore, none of the four deletion mutations or eight point mutations tested resulted in expression of the reporter gene in larvae, males, or inappropriate hermaphrodite tissues. Mutation of the VPE1 closest to the TATA box inactivated the promoter, in spite of the fact that four additional close matches to the VPE1 consensus sequence are present within the 5'-flanking 200 bp. Each of these upstream VPEl-like sequences could be mutated without loss of high-level transgene expression, suggesting that if these VPE1 sequences play a role in regulating vit-2, their effects are more subtle. A site-directed mutation in the overlapping VPE1 and VPE2 at -98 was sufficient to inactivate the promoter, indicating that one or both of these VPEs must be present for activation of vit-2 transcription. Similarly, a small perturbation of the VPE2 at -150 resulted in reduction of fp155 expression, while a more extensive mutation in this element eliminated expression. On the other hand, deletion of this VPE2 and all upstream DNA still permitted correctly regulated expression, although at a very low level, suggesting that this VPE2 performs an important role in activation of vit-2 expression but may not be absolutely required. The results, taken together, demonstrate that both VPE1 and VPE2 are sites for activation of the vit-2 promoter.

A 96-channel microfabricated capillary array electrophoresis (muCAE) device was evaluated for forensic short tandem repeat (STR) typing using PowerPlex 16 and AmpFlSTR Profiler Plus multiplex PCR systems. The high-throughput muCAE system produced high-speed <30-min parallel sample separations with single-base resolution. Forty-eight previously analyzed single-source samples were accurately typed, as confirmed on an ABI Prism 310 and/or the Hitachi FMBIO II. Minor alleles in 3:1 mixture samples containing female and male DNA were reliably typed as well. The instrument produced full profiles from sample DNA down to 0.17 ng, a threshold similar to that found for the ABI 310. Seventeen nonprobative samples from various evidentiary biological stains were also correctly typed. The successful application of the muCAE device to actual forensic STR typing samples is a significant step toward the development of a completely integrated STR analysis microdevice.

An integrated PCR sample cleanup and preconcentration process is developed for forensic short tandem repeat (STR) analysis using a streptavidin-modified photopolymerized capture gel injector for microchip capillary electrophoresis (microCE). PCR samples generated with one biotinylated primer and one fluorescent primer provide the input to the streptavidin-based affinity capture-microCE device. Monoplex PCR samples processed by the device exhibited approximately 10- to 50-fold increased fluorescence intensities, and DNA profiles generated using 9-plex STR samples displayed approximately 14- to 19-fold higher signal intensities compared to those analyzed using traditional cross injection. Complete STR profiles were obtained with as few as 25 copies of DNA template using the capture-microCE device. Four DNA samples with various degrees of degradation were also tested. Samples analyzed using the capture-microCE device resulted in a significant increase of successful allele detection. The ability of our capture-microCE device and method to remove contaminating ions, to concentrate the sample injection plug, and to eliminate electrokinetic injection bias provides a powerful approach for integrating sample cleanup with DNA separation.