Identification of a novel human member of the DEAD box protein family

Area of Science:

• Molecular Biology
• Genetics
• Immunology

Background:

• Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease targeting pancreatic beta cells.
• RNA helicases are crucial for various cellular processes, including RNA metabolism and cell division.
• The DEAD box protein family comprises essential RNA helicases with diverse functions.

Purpose of the Study:

• To identify novel autoantigens in patients with insulin-dependent diabetes mellitus.
• To characterize a newly isolated cDNA exhibiting homology to RNA helicases.
• To investigate the expression pattern of the novel protein.

Main Methods:

• Screening of a human pancreatic islet cDNA library using sera from IDDM patients.
• Sequence analysis of the isolated cDNA to determine protein homology and identify conserved motifs.
• Northern blot analysis to assess tissue-specific gene expression.

Main Results:

• Isolation of a novel cDNA, designated RNA helicase-like protein (RHELP), from the IDDM patient library.
• RHELP shares significant sequence homology with known DEAD box RNA helicases, including human p68 and yeast DBP2.
• Northern blot analysis confirmed RHELP expression in multiple tissues, including pancreatic islets, liver, lung, tonsil, thymus, and muscle.

Conclusions:

• RHELP is a newly identified member of the DEAD box RNA helicase family.
• The protein's expression in pancreatic islets and its potential role in RNA processing warrant further investigation.
• RHELP's potential function as a diabetic autoantigen requires further in vivo and in vitro studies.