ASH1 mRNA localization in yeast involves multiple secondary structural elements and Ash1 protein translation.

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Differential mating-type switching in yeast daughter cells relies on ASH1 mRNA localization.
• Previous studies identified the 3' untranslated region (3' UTR) as critical for RNA localization.
• The specific mechanisms governing ASH1 mRNA localization were not fully understood.

Purpose of the Study:

• To investigate the localization elements of ASH1 mRNA.
• To determine the role of the coding region versus the 3' UTR in ASH1 mRNA localization.
• To elucidate the factors responsible for the precise anchoring of ASH1 mRNA.

Main Methods:

• Analysis of ASH1 mRNA localization using reporter constructs.
• Identification of specific nucleotide regions responsible for localization.
• Investigation of the role of secondary structure and protein translation in localization.

Main Results:

• Localization elements of ASH1 mRNA are primarily located within its coding region, not the 3' UTR.
• A 77-nucleotide region near the stop codon, with specific secondary structures, is sufficient for bud localization.
• Efficient anchoring to the daughter cell cortex requires translation of Ash1 protein's carboxy-terminal sequences.

Conclusions:

• ASH1 mRNA localization is directed by sequences within its coding region, challenging previous models.
• Both RNA sequence elements and protein translation are essential for accurate mRNA localization and cell fate determination.
• This study reveals novel mechanisms for post-transcriptional gene regulation in asymmetric cell division.