miRBase Nomenclature not clear enough

Question

[biofalconch]

Hello all

I have been checking through miRBase, and have found three different ways they name their sequences. However, only two are explained (5p or 3p at the end), but there are some that do not have this identifiers, so I was hoping one of you could explain this to me.

Thanks in advance!

Answer 1

[Georg Summer]

http://www.mirbase.org/blog/2011/04/whats-in-a-name/

Might be helpful.

Answer 2

[Chirag Nepal]

Mirnas have two arms, which were previously annotated as mir/mir*. The general idea was, mir*(mir-star) were degraded. But as we started sequencing at higher coverage, previously thought mir* were also found to be expressed at reasonable depth (specifically in developmental stages/tissues). With this in mind, miR-Base changed the nomencleature, simply to denote the two arms as mir-5p/mir-3p. When you find only mir, then only one of the arm is expressed, compute the distance from pre-mirna to determine from which arm it is being expressed.