miRNeasy Mini Kit

Purification of total RNA including miRNA with the miRNeasy Mini Kit allows direct comparison of miRNA expression levels with those of housekeeping reference genes or any other mRNA of interest. Alternatively, for some sensitive downstream applications, an miRNA-enriched fraction without larger RNA may be required. miRNeasy Kits enable efficient enrichment of RNA down to approximately 18 nt in size. The presence of very small RNAs is clearly visible after purification using an miRNeasy Mini Kit, in contrast to samples prepared using an alternative kit (see figure "Effective enrichment of small RNA"). miRNeasy Kits efficiently purify RNA from both tissues and cells, even when low amounts of starting material are used. When RNA was purified from decreasing amounts of samples, C_T values increased linearly, indicating effective miRNA purification from a wide range  of starting material (see figure "Effective purification from a range of starting amounts").

RNA can be purified with the kit from a variety of tissues and cells, including difficult-to-lyse tissues (see figure "Efficient copurification from a wide range of tissues"). miRNeasy procedures eliminate the possibility of contamination with salts or phenol which could interfere with later analyses (see figure "Highly pure RNA without phenol carryover"). In addition to higher purity, miRNeasy Kits offer superior yields to alternative methods of miRNA purification, such as using TRIzol Reagent (see figure "miRNeasy Kit outperforms TRIzol"). RNA prepared using the miRNeasy Mini Kit is highly pure and ready for use in sensitive downstream applications.

The miRNeasy Mini Kit combines phenol/guanidine-based lysis of samples with silica-membrane–based purification of total RNA. QIAzol Lysis Reagent, included in the kit, is a monophasic solution of phenol and guanidine thiocyanate, designed to facilitate lysis of tissues, to inhibit RNases, and also to remove most of the cellular DNA and proteins from the lysate by organic extraction.

The miRNeasy Mini Kit enables purification of total RNA which includes RNA from 18 nucleotides (nt) upwards. Alternatively, an miRNA-enriched fraction and a total RNA (>200 nt) fraction can be can be purified separately (see flowchart "miRNeasy procedures"). The separate miRNA-enriched fraction may be required to reduce background in particularly sensitive downstream applications. For this specialized protocol, enabling enrichment of miRNAs and other small RNAs (<200 nt), the RNeasy MinElute Cleanup Kit is required.

Purification of totl RNA including miRNA with the miRNeasy Mini Kit can be automated on the QIAcube. The innovative QIAcube uses advanced technology to process QIAGEN spin columns, enabling seamless integration of automated, low-throughput sample prep into your laboratory workflow. Sample preparation using the QIAcube follows the same steps as the manual procedure (i.e., lyse, bind, wash, and elute) enabling you to continue using the miRNeasy Mini Kit for purification of high-quality RNA. More information about the automated procedure is available from the relevant protocol sheet.

The miRNeasy Mini Kit allows purification of miRNA with total RNA for use in a variety of applications, including:

• Northern blot analysis
• Quantitative, real-time RT-PCR
• Microarray analysis