Poster-Medicine-1993

The Nobel Prize in Physiology or Medicine 1993

Splicing errors cause thalassemia
	Thalassemia, a form of anemia common in the Mediterrarean countries, is caused by errors in the splicing process.

Normal red blood cells contain correctly spliced beta-globin, an important component in hemoglobin that takes up oxygen in the lungs.
	The red blood cells in thalassemia patients are distorted and sometimes immature, containing a nucleus. This is due to a point mutation in the beta-globin gene, which causes an error in splice site selection. A faulty beta-globin protein is made, leading to severe anemia.

Arrows mark two examples of sites where point mutations causing thalassemia occur in the beta-globin gene.
The Philadelphia chromosome and cancer
The small Philadelphia chromosome is present in cancer cells of almost all patients with chronic myeloic leukemia, a form of cancer of the blood. This chromosome is generated by breaks in the long arms of chromosomes 9 and 22 followed by an exchange of the tips of the chromosomes (translocation). This results in the creation of a fusion gene in the Ph chromosome, which then via a spliced mRNA, gives rise to a fusion protein. This abnormal protein is believed to play a key role in causing leukemia.

Contents:
Introduction » DNA makes RNA makes protein » Genes in pieces » The discovery of split genes » Altesplicing » Exon shuffling » Splicing and diseases
These pages are based on material from the 1993 Physiology or Medicine Nobel Poster. Credits and references for the poster »