Transcription of DmRP140, the gene coding for the second-largest subunit of RNA polymerase II

Identification and expression analysis of C3orf1, a novel human gene homologous to the Drosophila RP140-upstream gene

We have isolated C3orf1, a novel gene on human chromosome 3 showing homology to the Drosophila RP140-upstream gene. When mutated, RP140-upstream causes lethality in flies through an unknown mechanism, perhaps by interfering with transcription of the RP140 RNA polymerase subunit. The human C3orf1 gene encodes a predicted membrane protein of 32.2 kDa with four transmembrane domains without any other known motifs. Northern blot analysis showed generalized expression of C3orf1, enhanced in heart and skeletal muscle. EST database searching revealed the existence of a homologue gene in mouse. Thus, the C3orf1 gene is conserved and may perform an essential function in all tissues in mammals.