Tripartite motif (TRIM) proteins are also known as RBCC proteins as they comprise a RING domain, one or two B-boxes and a predicted coiled-coil region from the N- to C-terminus [
1]. The RING domain is a specialized zinc finger consisting of 40–60 residues that binds two zinc atoms. Studies have demonstrated that the RING domain of many TRIM proteins have ubiquitin E3 ligase activity [
2,
3]. B-boxes bind zinc atoms similar to the RING domain, and are found exclusively in TRIM proteins, although no function has been clearly assigned to these domains. The coiled-coil domain mainly participates in the homo-oligomeric and hetero-oligomeric interaction to form large protein complexes. Tripartite motif protein was first found in
Xenopus laevis as a novel zinc finger nuclear phosphoprotein (xnf7) [
4]. At present, tripartite motif proteins and their homologues have been identified in many species from primates to eels [
5], teleost fishes [
6] and nematodes [
7]. To date, many genes and pseudogene encoded tripartite motif proteins have been found in human and this is ever increasing [
8].
The tripartite motif proteins play multiple roles in a series of important cellular processes, including cell proliferation, differentiation; development, oncogenesis, apoptosis, and antiviral defense [
8–
10]. Many pathological symptoms, from Mendelian genetic diseases to cancer development and viral infection, frequently have a relationship with tripartite motif proteins [
11–
13]. In addition, TRIM family members represent a fast-growing list of antiviral molecules involved in the innate immunity. However, TRIM proteins need to be further studied to elucidate all the functions of this gene family [
8,
14]. In chicken, a cluster of TRIM-B30.2 genes including TRIM39 in the chicken MHC B locus has been identified flanking the chicken
BF/BL region and may be a candidate for genes affecting infectious disease [
15,
16].
In order to gain a better understanding of the chicken TRIM39, we have obtained the full-length cDNA sequence of TRIM39 and found an insertion of a base A at the position of 1006 bp compared to the sequence of TRIM39 in the NCBI database (NM-001006196) [
15]. Annotation of genetically mobile domains and the analysis of domain architectures found that the TRIM 39 proteins fulfill the TRIM rule of domain composition and has both PRY and SPRY domains. In addition, real time RT-PCR indicated that the amount of tripartite motif protein 39 is different in various tissues. The mRNA expression level was the highest in spleen and with a lower expression in liver, brain, and lung, suggesting that TRIM39 protein might be an interesting candidate affecting infectious disease.