Mir-10 Micro RNA Precursor Family - Pattern of Expression

Pattern of Expression

In adult animals, expression of miR-10 is limited to specific organs. The highest levels of miR-10a and miR-10b have been found in the kidneys of mice. Lower levels of miR-10a are seen in small intestine, lung and spleen, and lower levels of miR-10b are seen in skeletal muscle. Expression of miR-10b has also been detected in the ovaries. Adult zebrafish express miR-10a in heart, testis and ovary, and miR-10b in muscle and liver.

In developing embryos, miR-10 is detected at specific stages. Zebrafish embryos show miR-10a expression from 48 to 120 hours post-fertilisation, and miR-10b expression from 12 to 120 hours post-fertilisation. In Drosophila expression of miR-10-3p is highest in 12 to 24 hour old embryos and in 1st and 3rd instar larvae. Levels of miR-10-5p are highest in 12 to 24 hour old embryos and much lower in larvae.

In stage 5 Drosophila embryos (130–180 minutes post-fertilisation), miR-10 is distributed throughout 50-80% of the length of the egg. Later in development miRNA-10 becomes localised into bands, and levels decrease by stage 7 (195–200 minutes post-fertilisation). miR10 reappears by stage 11 (320–440 minutes post-fertilisation), where it is found in the ventral nerve cord, posterior midgut and hindgut. At stage 14 (620–680 hours post-fertilisation), miRNA-10 is localised to the posterior midgut and the anal pad. In Drosophila larvae, miR-10-3p is found in the imaginal discs (groups of cells which are destined to become adult structures upon metamorphosis). Expression of miR-10ba in mouse embryos shows a similar pattern to that of the Hoxb4 gene. Highest levels are found in the posterior trunk of the embryo, surrounding the hindlimb buds. Similarly, expression is restricted to the posterior trunk of chicken embryos. In Zebrafish embryos expression of miR-10 is also restricted to the posterior trunk, later in development it is further restricted to the spinal cord.