SEQUENCE OF A CDNA-ENCODING THE FERRITIN H-CHAIN FROM AN 11-WEEK-OLD HUMAN FETAL BRAIN

A cDNA library in lambda Charon BS(-) from 11-week-old human fetal bra in (FB) was screened using a human liver ferritin (FTH)-encoding cDNA as a probe. The complete sequence of the positive clone, cFB1, showed that the coding region and a part of the 5' and 3' untranslated region s (UTR) are identical to the corresponding published sequence of the l iver cDNA. However, a particularly noteworthy difference is the presen ce of 279 bp of additional sequence in the FB 3'-UTR. Northern blot an alysis of FB poly(A)+RNA showed it to be a part of the FTH transcript. Comparison of the 279-bp sequence with the GenBank and EMBL databases showed it to be 94.1, 62.5, and 58.9% similar to segments from human, mouse and rat FTH genomic sequences, respectively. However, in all th ese cases, only a part of this 279-bp sequence has been found in the n ontranscribed region. We therefore conclude that in FB, the 279-bp seq uence is a part of the mature FTH mRNA. Sequence analysis also suggest s a differential poly(A) site selection in the production of FTH mRNA in FB and liver.