Pathways Project: Annotation Walkthrough

The Pathways Project is focused on annotating genes found in well characterized signaling and metabolic pathways across the Drosophila genus. This walkthrough illustrates how to apply the GEP annotation strategy for the Pathways Project to construct a gene model for the Ras homolog enriched in brain (Rheb) gene in Drosophila yakuba.

A Simple Annotation Exercise

Dr. Justin R. DiAngelo (Penn State Berks) has developed an exercise that takes students through a series of steps to annotate a gene in a Drosophila biarmipes contig. Students will construct a gene model using gene predictions, BLASTX searches, and the GEP UCSC Genome Browser mirror. Students will then verify their final gene model using the Gene Model Checker.

Module TSS4: Annotation of Broad Transcription Start Sites

This module illustrates the use of computational (e.g., blastn) and experimental (e.g., RAMPAGE, CAGE, RNA PolII ChIP-Seq) data to define the narrow and wide TSS search regions for genes with broad promoters.

Module TSS2: Using Sequence Alignment to Identify a TSS

This module illustrates how pairwise (blastn) and multiple sequence alignments can be used in conjunction with RNA-Seq data and the Short Match functionality of the UCSC Genome Browser to facilitate the TSS annotation of the Antp gene in D. eugracilis.

Module 6. Alternative splicing

This module explores how multiple different mRNAs and polypeptides can be encoded by the same gene. After completing this module students will be able to explain how alternative splicing of a gene can lead to different mRNAs and illustrate how alternative splicing can lead to the production of different polypeptides and result in drastic changes in phenotype.

Module 5. Translation: The need for an Open Reading Frame

In this module students will learn how mRNA is translated into a string of amino acids. After completing this module students will be able to determine the codons for specific amino acids as well as start and stop codons. They will be able to identify open reading frames for a given gene, define the phases of splice donor and acceptor sites and describe how they impact the maintenance of the open reading frame.

Module 3. Transcription, Part II: What happens to the initial transcript made by RNA pol II?

This module demonstrates how the transcript generated by RNA polymerase II (the pre-mRNA) is processed to become mature mRNA using the sequence signals identified in Module 2. After completing this module students will be able to use the genome browser to explain the relationships among pre-mRNA, 5′ capping, 3′ polyadenylation, splicing, and mRNA.

Module 2. Transcription, Part I: From DNA sequence to transcription unit

This module illustrates how a primary transcript (pre-mRNA) is synthesized using a DNA molecule as the template. After completing this module students will be able to explain the importance of the 5′ and 3′ regions of the gene for initiation and termination of transcription by RNA polymerase II, and identify the beginning and end of a transcript using the capabilities of the genome browser (RNA-Seq, Short Match).