mRNA without main open reading frame?

[Keith Robison]

A number of RNAs have been reported which were found as cDNAs
but do not encode proteins.  XIST (the possible X-inactivation
switch) and H19 (forget the function -- but it's imprinted)
are two examples from mammals.  You might find a review on
XIST helpful.

Good luck!

Keith Robison
Harvard University
Department of Cellular and Developmental Biology
Department of Genetics / HHMI

robison at biosun.harvard.edu