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miR-11 microRNA precursor family (Final Draft)
The miR-11 microRNA is a short twenty one nucleotide RNA molecule that regulates gene expression. It is part of a single stranded group of RNAs called small temporal RNAs, that specifically regulate genes during development. The miR-11 microRNA is excised from the miR-11 microRNA precursor (~70 nucleotides long) by a ribonuclease called Dicer. Once cut out from the primary microRNA precursor, miR-11 can perform its function as a mature microRNA. MiR-11, like many other microRNAs, functions in post-transcriptional regulation of gene expression.

The miR-11 microRNA was initially believed to have been associated with the miR-2 microRNA family, but is now known to share a family motif with miR-6. Both miR-2 and miR-11 have similar seed regions, but there is little overlap in function and expression patterns between the two. These seed regions (6-8 nucleotides long) are used to target the RNA of interest and are located at the 5' end of animal mircroRNAs. The miR-11 microRNA and miR-6 share an almost identical seed region and have similar expression patterns and functional overlap.

These microRNAs are found in both invertebrates and vertebrates, but have been primarily studied in the model organism Drosophila melanogaster. The mir-11 gene is expressed in Drosophila melanogaster throughout all stages of development, but is decreased in adulthood. Decreased levels of the mir-11 gene in Drosophila embryos caused an increase in cell death. The miR-11 microRNA controls apoptosis through the regulation of proapoptotic genes.

Little is still know about the actual mechanisms behind mir-11 regulation and its functioning pathways.

Targets of miR-11
Some of the many genes regulated by miR-11 include:
 * dE2f1
 * reaper (rpr)
 * head involution defective (hid)
 * grim
 * sickle (skl)

dE2f1
The mir-11 gene is located within the last intron of the dE2f1 gene, a Drosophila homolog of the E2F1 human gene; Both mir-11 and dE2f1 are co-expressed. The dE2f1 gene is associated with both cell proliferation and DNA damage-induced apoptosis, meaning it functions in both the cell growth and programmed cell death pathways. The over-expression of mir-11 suppresses the apoptotic function of dE2f1, while a non-functional mutant mir-11 does not. In addition to this, over-expression of mir-11 has no direct impact on the cell proliferation function of dE2f1 . The mir-11 gene is only able to hinder the proapoptotic function of this Drosophila homolog.

Reaper (rpr)
Reaper is only expressed in the presence of DNA damage; it is expressed in cells that are destined to die. This proapoptotic gene is one of the first genes in the apoptosis pathway and is essential for the process of programmed cell death. It is directly regulated by dE2f1 and indirectly regulated by mir-11. When mir-11 is over-expressed rpr is suppressed and when mir-11 is suppressed rpr is over-expressed in the presence of dE2f1.

Head involution defective (hid)
The head involution defective gene is also regulated by dE2f1 and indirectly regulated by mir-11. This proapoptotic gene is transcriptionally expressed when dE2f1 is present within the cell. In the presence of infrared radiation or UV radiation induced DNA damage the accumulation of the Hid protein alone can not cause programmed cell death. Instead the expression of the reaper promoter sequence is needed to induce the transcription of p53, which then induces hid expression and ultimately leads to apoptosis.

Grim
Grim is not expressed in accordance with infrared radiation or UV radiation induced DNA damage ; grim has a similar amino-terminal to reaper and functions in a parallel pathway that leads to apoptosis. The over-expression of grim in Drosophila cell cultures is known to cause an increase in apoptosis. This gene is indirectly regulated by mir-11 through the regulation of dE2f1. Grim is suppressed in the presence of an over-expressed mir-11 and is over-expressed when mir-11 is suppressed.

Sickle (skl)
Sickle is another proapoptotic gene regulated by dE2f1, which is regulated by mir-11. This gene is expressed in all stages of Drosophila development, but suppressed in the adults.